Ethylene-vinyl alcohol copolymer resin particle composition

Abstract

The present invention aims to provide an ethylene-vinyl alcohol copolymer resin particle composition, and an ethylene-vinyl alcohol copolymer film and a multilayer structure made thereof. The present invention relates to an ethylene-vinyl alcohol copolymer (EVOH) resin particle composition, an ethylene-vinyl alcohol copolymer film made of the same, and a multilayer structure containing the same. The EVOH resin particle composition has a particle size of 0.00001 to 6 μm. 3 / μm 2 and a first EVOH resin particle having a surface peak volume (Vmp) of 0.00015 to 20 μm 3 / μm 2 and second EVOH resin particles having a surface peak portion having a substantial volume (Vmp) of 100 to 200 nm. The present invention can improve the processability and mechanical properties when the EVOH composition is formed into a film.

Description

[Technical Field]

[0001] The present invention relates to an ethylene-vinyl alcohol (EVOH) copolymer composition, and in particular to an ethylene-vinyl alcohol copolymer resin particle composition, and a film and a multilayer structure comprising the EVOH resin particle composition. [Background technology]

[0002] EVOH resins are widely used in laminates for preserving perishable goods. For example, EVOH resins and laminates made therefrom are commonly used in the food packaging, medical device and consumables, pharmaceutical, electronics, and agrochemical industries. Specifically, EVOH resins are typically applied in the form of films and can be incorporated into laminates as a separate layer, for example, to function as an oxygen barrier layer.

[0003] In practice, the industry has many requirements for the processability, mechanical properties, heat resistance, etc. of films made from EVOH materials. For example, if the EVOH film does not produce a large amount of gel particles (also known as fish eyes) on the surface after film formation, it has excellent processability, and if the EVOH film has good tensile elongation when stretched at a specific tensile force, it can be said to have ideal mechanical properties. Summary of the Invention [Problem to be solved by the invention]

[0004] However, no concept or means capable of effectively satisfying the above requirements has been proposed in the prior art. Focusing on this technical problem, the present inventors conducted research and found that when two types of EVOH resin particles contained in an EVOH resin particle composition have a specific range of values ​​for the effective volume (Vmp) of the surface peaks, a film made from the EVOH resin particle composition can be provided with good processability and mechanical properties. [Means for solving the problem]

[0005] Therefore, in one aspect, the present invention provides a method for producing a crystalline silicon nanoparticle having a particle size of 0.00001 to 6 μm. 3 / μm 2 and a first EVOH resin particle having a surface peak portion substantial volume (Vmp) of 0.00015 to 20 μm. 3 / μm 2 and second EVOH resin particles having a surface peak portion effective volume (Vmp) of 1000 nm.

[0006] According to some embodiments of the present invention, the Vmp of the second EVOH resin particles is greater than the Vmp of the first EVOH resin particles.

[0007] According to some embodiments of the present invention, the first EVOH resin particles have a melting point of 135 to 179°C, and the second EVOH resin particles have a melting point of 180 to 198°C.

[0008] According to some embodiments of the present invention, the first EVOH resin particles have an ethylene content of 36 to 50 mole percent.

[0009] According to some embodiments of the present invention, the ethylene content of the second EVOH resin particles is 20 to 35 mole percent.

[0010] According to some embodiments of the present invention, the EVOH resin particles have a cylindrical, elliptical cylindrical, rectangular prism, spherical, elliptical sphere, or go stone shape, and their major axis / height is 1 to 5 mm and their minor axis is 1 to 5 mm.

[0011] According to some embodiments of the present invention, the weight percentage of the first EVOH resin particles to the second EVOH resin particles is 5:95 to 75:25.

[0012] According to some embodiments of the present invention, the EVOH resin particle composition has a boron content of 5 to 550 ppm.

[0013] According to some embodiments of the present invention, the EVOH resin particle composition has an alkali metal content of 10 to 550 ppm.

[0014] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of kurtosis (Sku) of 0.0020-25, and the second EVOH resin particles have a surface parameter of kurtosis (Sku) of 0.0070-111.

[0015] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of maximum peak height (Sp) of a surface of 0.0005 to 29 μm, and the second EVOH resin particles have a surface parameter of maximum peak height (Sp) of a surface of 0.0020 to 63 μm.

[0016] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of a peak height (Spk) of 0.001 to 2 μm, and the second EVOH resin particles have a surface parameter of a peak height (Spk) of 0.003 to 22 μm.

[0017] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of extreme point height (Sxp) of 0.001 to 12 μm, and the second EVOH resin particles have a surface parameter of extreme point height (Sxp) of 0.002 to 48 μm.

[0018] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of arithmetic mean line height (Ra) of 0.001 to 0.990 μm, and the second EVOH resin particles have a surface parameter of arithmetic mean line height (Ra) of 0.001 to 0.990 μm.

[0019] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of maximum line height (Rz) of 0.001 to 9.900 μm, and the second EVOH resin particles have a surface parameter of maximum line height (Rz) of 0.001 to 9.900 μm.

[0020] In another aspect, the present invention provides an ethylene-vinyl alcohol copolymer film comprising the above-mentioned EVOH resin particle composition.

[0021] In yet another aspect, the present invention provides a multilayer structure comprising: (a) at least one layer of an ethylene-vinyl alcohol copolymer film comprising the above-described EVOH resin particle composition; (b) at least one polymer layer; and (c) at least one adhesive layer.

[0022] According to some embodiments of the present invention, the polymer layer is selected from the group consisting of a low density polyethylene layer, a polyethylene grafted maleic anhydride layer, a polypropylene layer, and a nylon layer, and the adhesive layer is a tie layer.

[0023] According to some embodiments of the present invention, the multilayer structure is polymer layer / adhesive layer / ethylene-vinyl alcohol copolymer film / adhesive layer / polymer layer. [Effects of the Invention]

[0024] The ethylene-vinyl alcohol copolymer (EVOH) resin particle composition, the ethylene-vinyl alcohol copolymer film comprising the same, and the multilayer structure comprising the film provided by the present invention can impart good processability and mechanical properties to a film comprising the EVOH resin particle composition, without being bound by any particular theory.

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present technology will be described in detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a schematic diagram showing the substantial volume of the surface ridge portion according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] It should be understood that the various aspects are not limited to the arrangements, instrumentality and characteristics shown in the drawings.

[0028] In one aspect, the present invention provides a method for producing a 0.00001 to 6 μm 3 / μm 2 and a first EVOH resin particle having a surface peak portion substantial volume (Vmp) of 0.00015 to 20 μm. 3 / μm 2 and second EVOH resin particles having a surface peak portion with a material volume (Vmp) of 1000 nm or less.

[0029] As used herein, the so-called surface peak volume (Vmp) refers to the volume at an areal coverage ratio p%, and its definition is defined in ISO 25178. The sizes of the core, protruding peaks, and protruding valleys can also be quantified by volume parameters. As shown in FIG. 1, Vmp represents the volume of the protruding peaks, Vmc represents the volume of the core, Vvc represents the volume of the space in the core, and Vvv represents the volume of the space in the protruding valleys. In the example shown in FIG. 1, the default range for the core is specified as 10% to 80%. The Vmp of the first EVOH resin particles is 0.00001 to 6 μm 3 / μm 2 , e.g., 0.00001, 0.00005, 0.00100, 0.00200, 0.00500, 0.01000, 0.05000, 0.10000, 0.50000, 1, 2, 3, 4, 5, or 6 μm 3 / μm 2The Vmp of the second EVOH resin particles is 0.00015 to 20 μm. 3 / μm 2 , for example 0.00015, 0.00050, 0.01000, 0.05000, 0.10000, 0.50000, 1, 5, 10, 15 or 20 μm 3 / μm 2 According to a preferred embodiment of the present invention, the Vmp of the second EVOH resin particles is greater than the Vmp of the first EVOH resin particles.

[0030] According to some embodiments of the present invention, the first EVOH resin particles have a melting point of 135 to 179°C, for example, 135, 140, 145, 150, 155, 160, 165, 170, 175, or 179°C. The second EVOH resin particles have a melting point of 180 to 198°C, for example, 180, 182, 184, 186, 188, 190, 192, 194, 196, or 198°C.

[0031] According to some embodiments of the present invention, the ethylene content of the first EVOH resin particles can be about 36 to 50 mole percent (mol%), such as 36, 38, 40, 42, 44, 46, 48, or 50 mol%, and the ethylene content of the second EVOH resin particles can be 20 to 35 mol%, such as 20, 21, 23, 25, 27, 29, 31, 33, or 35 mol%.

[0032] Additionally / or, the degree of saponification of the EVOH may be 90 mol % or more, preferably 95 mol % or more, preferably 97 mol % or more, preferably 99.5 mol % or more.

[0033] The EVOH particles referred to herein refer to the form and / or shape of one or more particles obtained by granulating an EVOH resin. Throughout the present invention, the EVOH particles are described as being granulated to form one or more EVOH particles. The EVOH particles can be processed into beads, cubes, chips, shavings, etc. According to some embodiments of the present invention, the EVOH resin particles have a cylindrical, elliptical, rectangular, spherical, oval, or go-stone shape, and their major axis or height is 1 to 5 mm, e.g., 1, 2, 3, 4, or 5 mm, and their minor axis is 1 to 5 mm, e.g., 1, 2, 3, 4, or 5 mm. As used herein, "major axis / height" refers to the longest outer diameter of an object whose surface is a closed curved surface, and "minor axis" refers to the smallest diameter of the cross section perpendicular to the major axis or height and having the largest area. As used herein, an "object whose surface is composed of closed curved surfaces" can be understood to mean an object whose entire surface is composed of curved surfaces, an object without edges or corners formed by the intersection of multiple surfaces, or an object whose cross section at any position does not exhibit a rectangular shape.

[0034] Specifically, when the EVOH resin particles are cylindrical or elliptical cylindrical, the height ranges from 1 to 5 mm, for example, 1.5 to 5.0 mm, 1.7 to 5.0 mm, 2.2 to 5.0 mm, 2.4 to 5.0 mm, 2.6 to 5.0 mm, 2.8 to 5.0 mm, 3.0 to 5.0 mm, 3.2 to 5.0 mm, 3.4 to 5.0 mm, 3.6 to 5.0 mm, 3.8 to 5.0 mm, 4.0 to 5.0 mm, 1.7 to 4.5 mm, 1.7 to 4.4 mm, 1.7 to 4.2 mm, 1.7 to 4.0 mm, 1.7 to 3.8 mm, 1.7 to 3.6 mm, 1.7 to 3.4 mm, 1.7 to 3.2 mm. The range of the minor axis is 1 to 5 mm, for example, 1.5 to 5.0 mm, 1.7 to 5.0 mm, 2.2 to 5.0 mm, 2.4 to 5.0 mm, 2.6 to 5.0 mm, 2.8 to 5.0 mm, 3.0 to 5.0 mm, 3.2 to 5.0 mm, 3.4 to 5.0 mm, 3.6 to 5.0 mm, 3.8 to 5.0 mm, 4.0 to 5.0 mm, 1.7 to 4.5 mm, 1.7 to 4.4 mm, 1.7 to 4.2 mm, 1.7 to 4.0 mm, 1.7 to 3.8 mm, 1.7 to 3.6 mm, 1.7 to 3.4 mm, 1.7 to 3.2 mm, and 1.7 to 3.0 mm.

[0035] When the EVOH particles are in the form of pellets, for example, spherical, oval, or go stone shapes, the range of the major axis is 1 to 5 mm, for example, 1.5 to 5.0 mm, 2.2 to 5.0 mm, 2.4 to 5.0 mm, 2.6 to 5.0 mm, 2.8 to 5.0 mm, 3.0 to 5.0 mm, 3.2 to 5.0 mm, 3.4 to 5.0 mm, 3.6 to 5.0 mm, 3.8 to 5.0 mm, 4.0 to 5.0 mm, 2.0 to 4.5 mm, 2.0 to 4.4 mm, 2.0 to 4.2 mm, 2.0 to 4.0 mm, 2.0 to 3.8 mm, 2.0 to 3.6 mm, 2.0 to 3.4 mm, 2.0 to 3.2 mm, 2.0 to 3.0 mm, The range of the minor axis is 1 to 5 mm, for example, 1.5 to 5.0 mm, 1.8 to 4.6 mm, 2.4 to 4.6 mm, 2.6 to 4.6 mm, 2.8 to 4.6 mm, 3.0 to 4.6 mm, 3.2 to 4.6 mm, 3.4 to 4.6 mm, 3.6 to 4.6 mm, 3.8 to 4.6 mm, 4.0 to 4.6 mm, 1.6 to 4.5 mm, 1.6 to 4.4 mm, 1.6 to 4.2 mm, 1.6 to 4.0 mm, 1.6 to 3.8 mm, 1.6 to 3.6 mm, 1.6 to 3.4 mm, 1.6 to 3.2 mm, 1.6 to 3.0 mm, and when the pellet is spherical, the major axis and the minor axis are equal.

[0036] According to some embodiments of the present invention, the weight percentage of the first EVOH resin particles to the second EVOH resin particles is 5:95 to 75:25, for example, 5:95, 15:85, 25:75, 35:65, 45:55, 55:45, 65:35, or 75:25.

[0037] According to some embodiments of the present invention, the EVOH resin particle composition may contain a boron compound, boric acid, cinnamic acid, alkali metal, conjugated polyene, lubricant, and / or alkaline earth metal, which can impart good properties to the EVOH resin particle composition.

[0038] According to some embodiments of the present invention, the EVOH resin particle composition may contain a boron compound, and the boron content of the EVOH resin particle composition may be 5 to 550 ppm. In some cases, the boron content of the EVOH resin particle composition relative to the total weight of the EVOH resin particle composition may be 10 to 450 ppm, 10 to about 400 ppm, 10 to about 350 ppm, 10 to about 300 ppm, 10 to about 275 ppm, 10 to about 250 ppm, 10 to about 225 ppm, 10 to about 200 ppm, 10 to about 175 ppm, about 20 to 450 ppm, about 20 to about 400 ppm, about 20 to about 350 ppm, or Approximately 20 to approximately 300ppm, approximately 20 to approximately 275ppm, approximately 20 to approximately 250ppm, approximately 20 to approximately 225ppm, approximately 20 to approximately 200ppm, approximately 20 to approximately 175ppm, approximately 60 to 450ppm, approximately 60 to approximately 400pp m, about 60 to about 350ppm, about 60 to about 300ppm, about 60 to about 275ppm, about 60 to about 250ppm, about 60 to about 225ppm, about 60 to about 200ppm, about 60 to about 175ppm, about 100 to 45 0ppm, about 100 to about 400ppm, about 100 to about 350ppm, about 100 to about 300ppm, about 100 to about 275ppm, about 100 to about 250ppm, about 100 to about 225ppm, about 100 to about 200p pm, about 100 to about 175ppm, about 140 to 450ppm, about 140 to about 400ppm, about 140 to about 350ppm, about 140 to about 300ppm, about 140 to about 275ppm, about 140 to about 250ppm, The boron content may be about 140 to about 225 ppm, about 140 to about 200 ppm, about 180 to about 450 ppm, about 180 to about 400 ppm, about 180 to about 350 ppm, about 180 to about 300 ppm, about 180 to about 275 ppm, about 180 to about 250 ppm, about 180 to about 225 ppm, about 220 to about 450 ppm, about 220 to about 400 ppm, about 220 to about 350 ppm, about 220 to about 300 ppm, or about 220 to about 275 ppm. When the boron content of the EVOH resin particle composition is within a certain range, the viscosity of the EVOH resin particle composition increases, reducing the possibility of the EVOH resin particle composition adhering to the screw, or removing the EVOH on the screw, providing the material with a self-cleaning function and further improving film thickness uniformity.According to a preferred embodiment of the present invention, in addition to the boron compound, the EVOH resin particle composition may contain cinnamic acid, an alkali metal, a conjugated polyene, an alkaline earth metal, a salt thereof, and / or a mixture thereof. The above-mentioned substances are commonly found in EVOH resin particle compositions and contribute to the EVOH resin particle composition's improved properties. When the content of the compound having a conjugated polyene structure is 1 to 30,000 ppm per unit weight of the EVOH resin particle composition, coloration after heating can be further suppressed, resulting in better thermal stability. When the content of the alkali metal compound or alkaline earth metal compound per unit weight of the EVOH resin composition is 10 to 550 ppm (in terms of metal), the EVOH resin composition can exhibit better moldability during long-term operation. The content may be, for example, between 10 and 550 ppm, between about 10 and 500 ppm, between about 10 and 450 ppm, between about 10 and 400 ppm, between about 10 and 350 ppm, between about 10 and 300 ppm, between about 10 and 250 ppm, between about 10 and 200 ppm, between about 10 and 150 ppm, between about 10 and 100 ppm, between about 10 and 50 ppm, between about 50 and 550 ppm, ppm, between about 50-500 ppm, between about 50 ppm and 450 ppm, between about 50-400 ppm, between about 50-350 ppm, between about 50-300 ppm, between about 50-250 ppm, between about 50-200 ppm, between about 50-150 ppm, between about 50-100 ppm, between about 100-550 ppm, between about 100-500 ppm, between about 100-450 ppm, between about 100 and 400 ppm, between about 100 and 350 ppm, between about 100 and 300 ppm, between about 100 and 250 ppm ppm, between about 100 and 200 ppm, between about 100 and 150 ppm, between about 200 and 550 ppm, between about 200 and 500 ppm, between about 200 and 450 ppm, between about 200 and 400 ppm, between about 200 and 350 ppm , between about 200 and 300 ppm, between about 200 and 250 ppm, between about 300 and 550 ppm, between about 300 and 500 ppm, between about 300 and 450 ppm, between about 300 and 400 ppm, between about 300 and 350 ppm, between about 400 and 550 ppm, between about 400 and 500 ppm, between about 400 and 450 ppm, or between about 500 and 550 ppm.

[0039] According to some embodiments of the present invention, the boron compound may comprise boric acid or a metal salt thereof, such as calcium borate, cobalt borate, zinc borate (e.g., zinc tetraborate, zinc metaborate), potassium aluminum borate, ammonium borate (e.g., ammonium metaborate, ammonium tetraborate, ammonium pentaborate, ammonium octaborate), cadmium borate (e.g., cadmium orthoborate, cadmium tetraborate), potassium borate (e.g., potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, potassium octaborate), silver borate (e.g., silver metaborate, silver tetraborate), copper borate (e.g., copper(II) borate, copper metaborate, copper tetraborate), sodium borate (e.g., sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate), or sodium borates (e.g., sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate). Examples of suitable borate salts include, but are not limited to, lead borate (e.g., lead metaborate, lead hexaborate), nickel borate (e.g., nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate), barium borate (e.g., barium orthoborate, barium metaborate, barium diborate, barium tetraborate), bismuth borate, magnesium borates (e.g., magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate), manganese borates (e.g., manganese(I) borate, manganese metaborate, manganese tetraborate), lithium borates (e.g., lithium metaborate, lithium tetraborate, lithium pentaborate), salts thereof, or combinations thereof. These may include borate minerals such as borax, kalinite, inyolite, kotolite, askarite / suanite, and szaibelyite, where borax, boric acid, and sodium borates (e.g., sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, and sodium octaborate) are preferably used.

[0040] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of kurtosis (Sku) of 0.0020 to 25, for example, about 0.0100 to 25, about 0.1000 to 25, about 1 to 25, about 1 to 23.3000, about 1 to 20, about 1 to 15, about 5 to 15, or about 7 to 10. The second EVOH resin particles have a surface parameter of kurtosis (Sku) of 0.0070 to 111, for example, about 0.0100 to 111, 0.0200 to 100, about 0.2000 to 65, about 2 to 50, about 2 to 40, about 10 to 40, or about 20 to 40.

[0041] As used herein, the definition of "surface parameter of kurtosis (Sku)" refers to ISO 25178:2012 and can be understood as the height distribution of the contour surface within the sampling range, and is a parameter that determines the sharpness of the surface shape.

[0042] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of maximum peak height (Sp) of the face of 0.0005 to 29 μm, e.g., about 0.0005 to 28 μm, about 0.0010 to 25 μm, about 0.0100 to 25 μm, about 0.1000 to 25 μm, about 1 to 25 μm, about 1 to 20 μm, about 1 to 15 μm, about 5 to 15 μm, or about 7 to 10 μm. The second EVOH resin particles have a surface parameter of a maximum peak height (Sp) of 0.0020 to 63 μm, for example, about 0.0020 to 60 μm, about 0.0200 to 60 μm, about 0.2000 to 60 μm, about 2 to 60 μm, about 10 to 60 μm, about 20 to 50 μm, about 25 to 40 μm, about 30 to 40 μm, or about 30 to 36 μm.

[0043] As used herein, the definition of "surface parameter of maximum surface peak height (Sp)" refers to ISO 25178:2012 and can be understood as the maximum value of the height above a reference surface within the sampling range.

[0044] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of a peak height (Spk) of 0.001 to 2 μm, e.g., about 0.001 to 2 μm, about 0.005 to 2 μm, about 0.010 to 2 μm, about 0.050 to 2 μm, about 0.100 to 2 μm, about 0.100 to 1 μm, or about 0.500 to 1 μm, and the second EVOH resin particles have a surface parameter of a peak height (Spk) of 0.003 to 22 μm, e.g., about 0.003 to 20 μm, about 0.030 to 20 μm, about 0.300 to 20 μm, about 1 to 20 μm, about 5 to 20 μm, about 5 to 15 μm, or about 5 to 10 μm.

[0045] As used herein, the definition of "surface parameter of peak height (Spk)" refers to ISO 25178:2012 and specifically means the average height of the peaks.

[0046] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of 0.001 to 12 μm, e.g., about 0.001 to 11 μm, about 0.005 to 10 μm, about 0.010 to 2 μm, about 0.050 to 2 μm, about 0.100 to 2 μm, about 0.100 to 1 μm, or about 0.500 to 1 μm, and the second EVOH resin particles have a surface parameter of 0.002 to 48 μm, e.g., about 0.003 to 48 μm, about 0.030 to 30 μm, about 0.300 to 20 μm, about 1 to 20 μm, about 5 to 20 μm, about 5 to 15 μm, or about 5 to 10 μm.

[0047] As used herein, the definition of "surface parameter of extreme point height (Sxp)" refers to ISO 25178:2012, and specifically refers to the difference in height between the average surface and the peaks on the surface after removing particularly high peaks on the surface, and the preset value indicates the difference in height between areal load ratios of 2.5% and 50%.

[0048] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of arithmetic mean line height (Ra) of 0.001 to 0.990 μm, e.g., about 0.001 to 0.990 μm, about 0.001 to 0.700 μm, about 0.001 to 0.500 μm, about 0.001 to 0.300 μm, about 0.001 to 0.100 μm, about 0.050 to 0.990 μm, about 0.050 to 0.700 μm, about 0.050 to 0.500 μm, about 0.050 to 0.300 μm, or about 0.050 to 0.100 μm. The second EVOH resin particles have a surface parameter of arithmetic mean line height (Ra) of 0.001 to 0.990 μm, for example, about 0.001 to 0.990 μm, about 0.001 to 0.700 μm, about 0.001 to 0.500 μm, about 0.010 to 0.300 μm, about 0.010 to 0.100 μm, about 0.050 to 0.990 μm, about 0.050 to 0.700 μm, about 0.050 to 0.500 μm, about 0.050 to 0.300 μm, or about 0.050 to 0.100 μm.

[0049] As used in this specification, the "surface parameter of the arithmetic mean height of the line (Ra)" is a parameter that represents surface roughness, and its definition refers to JIS B 0601, and specifically can be understood as the average of the absolute values ​​of the profile curve over a reference length.

[0050] According to some embodiments of the present invention, the first EVOH resin particles have a surface parameter of maximum line height (Rz) of 0.0010 to 9.9000 μm, e.g., about 0.0010 to 9 μm, about 0.0010 to 7 μm, about 0.0010 to 5 μm, about 0.0100 to 3 μm, about 0.0500 to 5 μm, about 0.0500 to 3 μm, about 0.0500 to 1 μm, or about 0.0500 to 0.0800 μm. The second EVOH resin particles have a surface parameter of maximum line height (Rz) of 0.0010 to 9.9000 μm, for example, about 0.0800 to 9 μm, about 0.1000 to 9 μm, about 0.1500 to 9 μm, about 0.1500 to 7 μm, about 0.5000 to 5 μm, about 0.5000 to 2.5000 μm, or about 1 to 2.5000 μm. As used herein, the "surface parameter of maximum line height (Rz)" is a parameter representing surface roughness, and its definition is based on JIS B 0601. Specifically, it can be understood as the distance from the lowest valley to the highest peak in a profile curve over a reference length.

[0051] In another aspect, the present invention provides an ethylene-vinyl alcohol copolymer film comprising the above-mentioned EVOH resin particle composition. Specifically, the ethylene-vinyl alcohol copolymer film is a monolayer film.

[0052] In yet another aspect, the present invention provides a multilayer structure comprising: (a) at least one layer of an ethylene-vinyl alcohol copolymer film comprising the above-described EVOH resin particle composition; (b) at least one polymer layer; and (c) at least one adhesive layer.

[0053] According to some embodiments of the present invention, the polymer layer is selected from the group consisting of a low-density polyethylene layer, a polyethylene-grafted maleic anhydride layer, a polypropylene layer, and a nylon layer, and the adhesive layer is, for example, a tie layer of ARKEMA OREVAC 18729 manufactured by ARKEMA. Specifically, the multilayer structure has a layered structure of a polymer layer, an adhesive layer, an ethylene-vinyl alcohol copolymer film, an adhesive layer, and a polymer layer in this order. According to some embodiments of the present invention, the thickness of the polymer layer is 100 to 500 μm, preferably 200 to 400 μm, and more preferably 300 μm; the thickness of the adhesive layer is 10 to 40 μm, preferably 20 to 30 μm, and more preferably 25 μm; and the thickness of the ethylene-vinyl alcohol copolymer film is 20 to 80 μm, preferably 40 to 60 μm, and more preferably 50 μm.

[0054] Without being limited to a particular theory, it is believed that the effective volume (Vmp) of the surface peaks is the main factor affecting the thermal conductivity of the chip, and is therefore related to the melting conditions during material processing, which further affects the uniformity of thermal conduction of the first EVOH resin particles and the second EVOH resin particles during processing. Therefore, when the Vmp values ​​of the first EVOH resin particles and the second EVOH resin particles in an EVOH resin particle composition are within a certain range, if the surface roughness of the EVOH peaks with a high melting point is large, the peaks will melt first during processing, making the thermal conduction of the plastic particles relatively uniform and increasing the temperature in the melting region. If the surface roughness of the EVOH peaks with a low melting point is small, localized overheating of the peaks during processing can be reduced. Therefore, by controlling the effective volume (Vmp) of the surface peaks of the two EVOH resin particles and adjusting the thermal conduction conditions after melt-kneading, a uniform melting can be achieved, resulting in an EVOH film that subsequently exhibits both good processability and mechanical properties. [Example]

[0055] The following non-limiting examples of the present invention will be used to explain the various aspects and advantages of the present invention. The EVOH formulations in the examples and comparative examples were prepared from at least two components. More specifically, the two components of the EVOH resin particle compositions in the examples and comparative examples were two types of EVOH resin particles.

[0056] Preparation of EVOH Resin Particle Composition Non-limiting methods for preparing EVOH resin particle compositions are provided below. Five non-limiting example EVOH resin particle compositions (Examples EVOH1-5) and six comparative examples (Comparative Examples EVOH1-6) were prepared according to methods similar to those disclosed below. However, the specific methods for preparing Examples EVOH1-5 and Comparative Examples EVOH1-6 generally differ in one or more aspects from the methods disclosed below.

[0057] (First EVOH resin particles of Example 1) 500 kg of vinyl acetate, 100 kg of methanol, 0.0585 kg of acetyl peroxide, and 0.015 kg of citric acid were added to a polymerization vessel equipped with a cooling coil, and the atmosphere in the polymerization vessel was once replaced with nitrogen and then with ethylene until the ethylene pressure reached 45 kg / cm. 2 The pressure was increased until the temperature reached 67°C while stirring under ethylene pressure to initiate polymerization. Six hours after the start of polymerization, when the polymerization rate reached 60%, 0.0525 kg of sorbic acid conjugated polyene was added as a polymerization inhibitor. In this way, an ethylene-vinyl acetate copolymer with an ethylene structural unit content of 44 mol% was obtained. Next, the reaction liquid containing the ethylene-vinyl acetate copolymer was fed into a distillation column, and methanol vapor was blown in from the bottom of the column to remove unreacted vinyl acetate, yielding a methanol solution of the ethylene-vinyl acetate copolymer.

[0058] In this example, a component obtained by polymerizing ethylene monomer and vinyl acetate monomer (ethylene-vinyl acetate copolymer, hereinafter referred to as "EVAC" polymer) was saponified to a saponification degree of 99.5% to form EVOH. The EVOH was then dissolved in an aqueous alcohol solution with a methanol / water ratio of 70:30. To promote dissolution of the EVOH in the EVOH / methanol / water solution, the EVOH / methanol / water solution was kept at 60°C for 1 hour. The solids content of the EVOH / methanol / water solution was 41 wt%.

[0059] Next, the methanol, water, and EVOH solution was granulated using a strip cutter. Specifically, the methanol, water, and EVOH solution was pumped through a supply pipe at a flow rate of 120 L / min and then fed into a die with a circular opening of 0.5 mm in diameter. The EVOH solution was extruded into a water / methanol mixture (water / methanol mass ratio = 9 / 1) at 5°C, precipitated into strands, and cut with a rotary blade at 500 rpm to obtain EVOH particles. The EVOH particles were then centrifuged to separate the EVOH particles, which were then washed with water. The above-mentioned centrifugal dehydration process was then repeated a second time. The EVOH particles were then immersed in a boric acid / sodium acetate solution, followed by a drying process, and calcium stearate was added to obtain the final EVOH resin particle product. The drying was divided into three stages: the first stage was drying using a band dryer at 80°C for 2 hours; the second stage was drying using a band dryer at 100°C for 20 hours; and the third stage was drying using a fluidized bed dryer at 120°C for 20 hours. Finally, the particles were transported. The transportation was carried out under the following conditions: pneumatic transportation, pipeline diameter 6 inches, number of elbows 4, pipeline length 30 meters, and transportation speed 40 meters / min. The first EVOH resin particles in this example were cylindrical with a height of 5 mm and a minor axis of 1 mm.

[0060] In the above-mentioned centrifugation and washing steps, the rotation speed of the first dehydrator was 5000 rpm, the water / wet particle ratio during pumping was 10, the centrifugal pump used for pumping was an open type, the rotation speed of the pump was 3000 rpm, the water / wet particle weight ratio during washing was 5, the water flow rate during washing was 2 m / min, and the rotation speed of the second dehydrator was 2000 rpm.

[0061] (Second EVOH resin particles of Example 1) The second EVOH resin particles of Example 1 were prepared in a similar manner to the above. The difference was that an ethylene-vinyl acetate copolymer (hereinafter referred to as "EVAC") with an ethylene content of 32 mol% was saponified to a saponification degree of 99.5% to prepare the EVOH polymer. The diameter of the die with the strand-cutting opening was 2 mm, and the rotation speed of the rotary blade was 2000 rpm.

[0062] In the centrifugation and washing steps for the second EVOH resin particles of this embodiment, the rotation speed of the first dehydrator was 3000 rpm, the water / wet particle ratio during pumping was 3, the centrifugal pump for pumping was an open type, the rotation speed of the pump was 2000 rpm, the water / wet particle weight ratio during washing was 3, the water flow rate during washing was 2.5 m / min, and the rotation speed of the second dehydrator was 3000 rpm. The final product of the second EVOH resin particles of this embodiment is cylindrical with a height of 2 mm and a minor axis of 3 mm.

[0063] For use in further processing, the first EVOH resin particles and the second EVOH resin particles were mixed in a ratio of 25 wt % and 75 wt %, respectively, with the EVOH resin particle composition of Example 1, and the mixture was continuously mixed at 10 rpm for 5 minutes using a conical screw mixer (Model: CM-2, purchased from Xiehui Machinery Industrial Co., Ltd.).

[0064] (First and second EVOH resin particles of Example 2) The first and second EVOH methanol aqueous solutions used in Example 2 were prepared using a process similar to that used to prepare the EVOH resin particles in Example 1. However, the ethylene content of the first EVOH methanol aqueous solution in Example 2 was 48 mol %, and the methanol, water, and EVOH solution was pelletized using underwater pelletization. Specifically, the methanol, water, and EVOH solution was pumped through a supply pipe at a flow rate of 120 L / min, then fed into a 1 mm diameter inlet pipe and cut with a rotary blade at 1500 rpm to obtain EVOH particles. The EVOH particles were then cooled with circulating condensed water at 5°C. The EVOH particles were then centrifuged to separate the EVOH particles, which were then washed with water. This was followed by a second centrifugation dehydration step, after which the EVOH particles were immersed in a boric acid / sodium acetate solution, followed by a drying step, and calcium stearate was added to obtain the final EVOH resin particles. The first EVOH resin particles of this example are elliptical in shape with a major axis of 3 mm and a minor axis of 2 mm.

[0065] In the centrifugal separation and washing processes employed, the rotation speed of the first dehydrator is 3000 rpm, the water / wet particle ratio during pumping is 10, the centrifugal pump used for pumping is semi-open type, the rotation speed of the pump is 4000 rpm, the water / wet particle weight ratio during water washing is 10, the water flow rate during water washing is 2 m / min, and the rotation speed of the second dehydrator is 1000 rpm. Finally, the first EVOH resin particle product has an oval spherical shape with a major axis of 3 mm and a minor axis of 2 mm.

[0066] The first EVOH methanol aqueous solution of Example 2 was prepared using a process similar to that used to prepare the first EVOH resin particles of Example 2, with an inlet pipe diameter of 2 mm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 2000 rpm, the water / wet particle ratio during pumping was 5, the centrifugal pump used for pumping was a sealed type, the rotation speed of the pump was 1000 rpm, the water / wet particle weight ratio during washing was 10, the water flow rate during washing was 5 m / min, and the rotation speed of the second dehydrator was 3000 rpm. Finally, the second EVOH resin particles were spherical with a minor axis of 3 mm. The first EVOH resin particles and the second EVOH resin particles were mixed into the EVOH resin particle composition of Example 2 at a ratio of 10 wt % and 90 wt %, respectively.

[0067] (First and second EVOH resin particles of Example 3) The first EVOH methanol aqueous solution used in Example 3 was prepared using a process similar to that for the EVOH resin particles in Example 2. However, the ethylene content of the first EVOH methanol aqueous solution in Example 3 was 38 mol %, and the process similar to that for the first EVOH resin particles in Example 2 was used. The inlet pipe diameter was 0.5 mm, and the rotary blade rotation speed was 3000 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 2500 rpm, the water / wet particle ratio during pumping was 8, the centrifugal pump used for pumping was an open type, the rotation speed of the pump was 5000 rpm, the water / wet particle weight ratio during water washing was 8, the water flow rate during water washing was 2.5 m / min, and the rotation speed of the second dehydrator was 3000 rpm. Finally, the first EVOH resin particles produced were spherical with a minor axis of 1 mm.

[0068] The second EVOH aqueous methanol solution of Example 3 was prepared using a process similar to that of Example 1. The ethylene content was 29 mol%, the diameter of the die with the strand-cutting opening was 4 mm, and the rotation speed of the rotary blade was 3000 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 1000 rpm, the water / wet particle ratio during pumping was 5, the centrifugal pump for pumping was semi-open, the rotation speed of the pump was 5000 rpm, the water / wet particle weight ratio during washing was 5, the water flow rate during washing was 5 m / min, and the rotation speed of the second dehydrator was 4000 rpm. Finally, the second EVOH resin particles were cylindrical with a height of 1 mm and a minor axis of 5 mm. The first EVOH resin particles and the second EVOH resin particles were mixed in a ratio of 50 wt% and 50 wt% to the EVOH resin particle composition of Example 3.

[0069] (First and second EVOH resin particles of Example 4) The first EVOH resin particles used in Example 4 were prepared using a process similar to that for the EVOH resin particles in Example 2. However, when the first EVOH methanol aqueous solution in Example 4 was prepared, the ethylene content was 48 mol%, the inlet pipe diameter was 0.5 mm, and the rotary blade rotation speed was 500 rpm. In the centrifugation and washing processes used, the rotation speed of the first dehydrator was 2500 rpm, the water / wet particle ratio during pumping was 6, the centrifugal pump used for pumping was a semi-open type, the rotation speed of the pump was 5000 rpm, the water / wet particle weight ratio during water washing was 7, the water flow rate during water washing was 2 m / min, and the rotation speed of the second dehydrator was 4000 rpm. Finally, the first EVOH resin particles produced were ellipsoidal with a major axis of 5 mm and a minor axis of 1 mm.

[0070] The second EVOH aqueous methanol solution of Example 4 was prepared using a process similar to that of Example 1, with an ethylene content of 32 mol%, a die diameter of 2 mm for strand-cutting openings, and a rotary blade rotation speed of 1500 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 3000 rpm, the water / wet particle ratio during pumping was 9, the centrifugal pump for pumping was an open type, the rotation speed of the pump was 4000 rpm, the water / wet particle weight ratio during water washing was 10, the water flow rate during water washing was 5 m / min, and the rotation speed of the second dehydrator was 4000 rpm. Finally, the second EVOH resin particles were cylindrical with a height of 3 mm and a minor axis of 3 mm. The first EVOH resin particles and the second EVOH resin particles were mixed into the EVOH resin particle composition of Example 4 at a ratio of 15 wt % and 85 wt %, respectively.

[0071] (First and second EVOH resin particles of Example 5) The first and second EVOH resin particles used in Example 5 were prepared using a process similar to that for the EVOH resin particles in Example 2. However, when the first EVOH methanol aqueous solution in Example 5 was prepared, the ethylene content was 38 mol%, the inlet pipe diameter was 1 mm, and the rotary blade rotation speed was 1000 rpm. In the centrifugation and washing processes used, the rotation speed of the first dehydrator was 4000 rpm, the water / wet particle ratio during pumping was 7, the centrifugal pump used for pumping was an open type, the rotation speed of the pump was 3000 rpm, the water / wet particle weight ratio during water washing was 8, the water flow rate during water washing was 7 m / min, and the rotation speed of the second dehydrator was 2000 rpm. Finally, the first EVOH resin particles produced were oval spheres with a major axis of 4 mm and a minor axis of 2 mm.

[0072] The ethylene content of the second EVOH aqueous methanol solution in Example 5 was 24 mol%, the inlet pipe diameter was 0.5 mm, and the rotary blade rotation speed was 1000 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 5000 rpm, the water / wet particle ratio during pumping was 9, the centrifugal pump used for pumping was a semi-open type, the rotation speed of the pump was 3000 rpm, the water / wet particle weight ratio during washing was 10, the water flow rate during washing was 6 m / min, and the rotation speed of the second dehydrator was 1000 rpm. Finally, the second EVOH resin particle product was ellipsoidal with a major axis of 4 mm and a minor axis of 1 mm. The first EVOH resin particles and the second EVOH resin particles were mixed in a ratio of 35 wt% and 65 wt%, respectively, with the EVOH resin particle composition of Example 4.

[0073] (First and second EVOH resin particles of Comparative Example 1) The first EVOH resin particles used in Comparative Example 1 were prepared using a process similar to that of Example 2. However, when the first EVOH methanol aqueous solution in Comparative Example 1 was prepared, the ethylene content was 44 mol%, the inlet pipe diameter was 2.5 mm, and the rotary blade rotation speed was 1200 rpm. In the centrifugation and washing processes used, the rotation speed of the first dehydrator was 2000 rpm, the water / wet particle ratio during pumping was 10, the centrifugal pump used for pumping was an open type, the rotation speed of the pump was 1000 rpm, the water / wet particle weight ratio during water washing was 15, the water flow rate during water washing was 2 m / min, and the rotation speed of the second dehydrator was 1000 rpm. Finally, the first EVOH resin particles produced were spherical with a minor axis of 3.5 mm.

[0074] The second EVOH aqueous methanol solution of Comparative Example 1 was prepared using a process similar to that of Example 1. The ethylene content was 29 mol%, the diameter of the die with the strand-cutting opening was 3.5 mm, and the rotation speed of the rotary blade was 500 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 1000 rpm, the water / wet particle ratio during pumping was 15, the centrifugal pump for pumping was an open type, the rotation speed of the pump was 2000 rpm, the water / wet particle weight ratio during water washing was 20, the water flow rate during water washing was 1 m / min, and the rotation speed of the second dehydrator was 1000 rpm. Finally, the second EVOH resin particles were cylindrical, 5 mm high and 4.5 mm short diameter. The first EVOH resin particles and the second EVOH resin particles were mixed into the EVOH resin particle composition of Comparative Example 1 at 5 wt% and 95 wt%, respectively.

[0075] (First and second EVOH resin particles of Comparative Example 2) The first EVOH resin particles used in Comparative Example 2 were prepared using a process similar to that of Example 2. However, when the first EVOH methanol aqueous solution in Comparative Example 2 was prepared, the ethylene content was 35 mol%, the inlet pipe diameter was 1 mm, and the rotary blade rotation speed was 1500 rpm. In the centrifugation and washing processes used, the rotation speed of the first dehydrator was 3000 rpm, the water / wet particle ratio during pumping was 20, the centrifugal pump used for pumping was an open type, the rotation speed of the pump was 1000 rpm, the water / wet particle weight ratio during water washing was 15, the water flow rate during water washing was 1.5 m / min, and the rotation speed of the second dehydrator was 2000 rpm. Finally, the first EVOH resin particles produced were oval spheres with a major axis of 3 mm and a minor axis of 2 mm.

[0076] The first EVOH resin particles of Comparative Example 2 were prepared using a process similar to that of Example 1. However, when preparing the second EVOH methanol aqueous solution of Comparative Example 2, the ethylene content was 24 mol%, the diameter of the die with the strand-cutting opening was 1 mm, and the rotation speed of the rotary blade was 1000 rpm. In the centrifugation and washing steps employed, the rotation speed of the first dehydrator was 8000 rpm, the water / wet particle ratio during pumping was 1, the centrifugal pump used for pumping was a sealed type, the rotation speed of the pump was 8000 rpm, the weight ratio of water / wet particle during water washing was 1, the water flow rate during water washing was 8 m / min, and the rotation speed of the second dehydrator was 5000 rpm. Finally, the second EVOH resin particles produced were cylindrical with a height of 4 mm and a minor axis of 2 mm. Furthermore, the first EVOH resin particles and the second EVOH resin particles were mixed into the EVOH resin particle composition of Comparative Example 2 at a ratio of 75 wt % and 25 wt %, respectively.

[0077] (First and second EVOH resin particles of Comparative Example 3) The first and second EVOH resin particles of Comparative Example 3 were prepared using a process similar to that of Example 1. However, when the first EVOH aqueous methanol solution of Comparative Example 3 was prepared, the ethylene content was 48 mol%, the diameter of the die with the strand-cutting opening was 3 mm, and the rotation speed of the rotary blade was 1700 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 7000 rpm, the water / wet particle ratio during pumping was 3, the centrifugal pump used for pumping was a closed type, the rotation speed of the pump was 7000 rpm, the weight ratio of water / wet particle during water washing was 1, the water flow rate during water washing was 7 m / min, and the rotation speed of the second dehydrator was 6000 rpm. Finally, the first EVOH resin particles were cylindrical with a height of 2.5 mm and a minor axis of 4 mm. The ethylene content of the second EVOH aqueous methanol solution of Comparative Example 3 was 32 mol%, the diameter of the die with the strand-cutting opening was 2 mm, and the rotation speed of the rotary blade was 1200 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 6000 rpm, the water / wet particle ratio during pumping was 1, the centrifugal pump used for pumping was a sealed type, the rotation speed of the pump was 6000 rpm, the weight ratio of water / wet particle during washing was 3, the water flow rate during washing was 6 m / min, and the rotation speed of the second dehydrator was 5000 rpm. Finally, the second EVOH resin particle product was cylindrical with a height of 3.5 mm and a minor axis of 3 mm. The first EVOH resin particles and the second EVOH resin particles were mixed into the EVOH resin particle composition of Comparative Example 3 at a ratio of 15 wt % and 85 wt %, respectively.

[0078] (First and second EVOH resin particles of Comparative Example 4) The first and second EVOH resin particles of Comparative Example 4 were prepared using a process similar to that of Example 2. However, when the first EVOH methanol aqueous solution of Comparative Example 4 was prepared, the ethylene content was 38 mol%, the inlet pipe diameter was 0.5 mm, and the rotary blade rotation speed was 3000 rpm. In the centrifugation and washing steps used, the first dehydrator rotation speed was 3000 rpm, the water / wet particle ratio during pumping was 8, the centrifugal pump used for pumping was an open type, the pump rotation speed was 4000 rpm, the water / wet particle weight ratio during water washing was 8, the water flow rate during water washing was 2.5 m / min, and the second dehydrator rotation speed was 3000 rpm. Finally, the first EVOH resin particles were spherical with a minor axis of 1 mm. When the second EVOH methanol aqueous solution of Comparative Example 4 was prepared, the ethylene content was 27 mol%, the inlet pipe diameter was 3 mm, and the rotary blade rotation speed was 1000 rpm. In the centrifugal separation and washing steps, the rotation speed of the first dehydrator was 8000 rpm, the water / wet particle ratio during pumping was 1, the centrifugal pump for pumping was a sealed type, the rotation speed of the pump was 8000 rpm, the water / wet particle weight ratio during water washing was 3, the water flow rate during water washing was 6 m / min, and the rotation speed of the second dehydrator was 6000 rpm. Finally, the second EVOH resin particle product was spherical with a minor axis of 4 mm. Furthermore, the first EVOH resin particles and the second EVOH resin particles were mixed in a ratio of 10 wt% and 90 wt%, respectively, with the EVOH resin particle composition of Comparative Example 4.

[0079] (First and second EVOH resin particles of Comparative Example 5) The first and second EVOH resin particles of Comparative Example 5 were prepared using a process similar to that of Example 2. However, when the first EVOH aqueous methanol solution of Comparative Example 5 was prepared, the ethylene content was 44 mol%, the inlet pipe diameter was 2.5 mm, and the rotary blade rotation speed was 1000 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 1000 rpm, the water / wet particle ratio during pumping was 10, the centrifugal pump used for pumping was an open type, the pump rotation speed was 3000 rpm, the water / wet particle weight ratio during water washing was 10, the water flow rate during water washing was 1 m / min, and the rotation speed of the second dehydrator was 1000 rpm. Finally, the first EVOH resin particles were oval spheres with a major axis of 4 mm and a minor axis of 3.5 mm. The ethylene content of the second EVOH aqueous methanol solution of Comparative Example 5 was 29 mol%, the diameter of the inlet pipe was 0.5 mm, and the rotation speed of the rotary blade was 1700 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 3000 rpm, the water / wet particle ratio during pumping was 5, the centrifugal pump used for pumping was a sealed type, the rotation speed of the pump was 2000 rpm, the weight ratio of water / wet particle during washing was 10, the water flow rate during washing was 5 m / min, and the rotation speed of the second dehydrator was 3000 rpm. Finally, the second EVOH resin particle product was oval spheres with a major axis of 2.5 mm and a minor axis of 1 mm. The first EVOH resin particles and the second EVOH resin particles were mixed in a ratio of 20 wt% and 80 wt%, respectively, with the EVOH resin particle composition of Comparative Example 5.

[0080] (First and second EVOH resin particles of Comparative Example 6) The first and second EVOH resin particles of Comparative Example 6 were prepared using a process similar to that of Example 2. However, when the first EVOH aqueous methanol solution of Comparative Example 6 was prepared, the ethylene content was 38 mol%, the inlet pipe diameter was 1.5 mm, and the rotary blade rotation speed was 1700 rpm. In the centrifugation and washing steps, the rotation speed of the first dehydrator was 7000 rpm, the water / wet particle ratio during pumping was 2, the centrifugal pump used for pumping was a closed type, the pump rotation speed was 8000 rpm, the water / wet particle weight ratio during water washing was 3, the water flow rate during water washing was 10 m / min, and the rotation speed of the second dehydrator was 6000 rpm. Finally, the first EVOH resin particles were spherical with a minor axis of 2.5 mm. When the second EVOH aqueous methanol solution of Comparative Example 6 was prepared, the ethylene content was 32 mol%, the inlet pipe diameter was 0.5 mm, and the rotary blade rotation speed was 1000 rpm. In the centrifugal separation and washing steps, the rotation speed of the first dehydrator was 1000 rpm, the water / wet particle ratio during pumping was 3, the centrifugal pump for pumping was a semi-open type, the rotation speed of the pump was 3000 rpm, the water / wet particle weight ratio during washing was 5, the water flow rate during washing was 3 m / min, and the rotation speed of the second dehydrator was 4000 rpm. Finally, the second EVOH resin particle product was oval spheres with a major axis of 4 mm and a minor axis of 1 mm. Furthermore, the first EVOH resin particles and the second EVOH resin particles were mixed in a ratio of 35 wt% and 65 wt%, respectively, with the EVOH resin particle composition of Comparative Example 6.

[0081] EVOH resin particle parameters The parameters of the EVOH resin particles of the present invention and the methods for their evaluation / analysis are shown below.

[0082] Particle surface roughness To evaluate and analyze the surface roughness of the EVOH resin particles in the examples, the EVOH resin particles were placed flat on a plate and the particle surface roughness was measured. To ensure that the scanning plane was relatively horizontal during measurement, data with a slope greater than 0.5 must be excluded (slope = maximum surface height Sz / edge length of analysis area 129 μm). Images were taken using an Olympus LEXT OLS5000-SAF laser microscope at an ambient temperature of 24±3°C and a relative humidity of 63±3%. The filter was set to filterless. The light source was a 405 nm wavelength light source. The objective lens was a 100x magnification (MPLAPON-100xLEXT). The optical zoom was set to 1.0x. The image area was set to 129 μm x 129 μm (the center line of the image area was used to measure Rz). The resolution was set to 1024 pixels x 1024 pixels. Values ​​were measured for 100 particles and averaged. Of these, Vmp, Sku, Sp, Spk, and Sxp were measured in accordance with the method described in ISO 25178:2012, and Ra and Rz were measured in accordance with the method described in JIS B 0601 (2001).

[0083] Ethylene content analysis In the present invention, in order to evaluate and analyze the ethylene content of the EVOH resin particles of the embodiment, a Raman spectrometer manufactured by UniDRON was used, and the ethylene content in each EVOH resin particle was measured at five random points using a laser light source with a wavelength of 473 nm, and the average value was taken as the ethylene content value of the EVOH resin particle sample.

[0084] Melting point analysis The melting temperature of the EVOH resin particles was measured using a DSC Q200 device (manufactured by TZERO TECHNOLOGIES, INC., Tzero lid: TA Instruments T170607, Tzero pan: TA Instruments T170620) in accordance with the method described in ISO 11357-3-2011.

[0085] In practice, without being bound by any particular theory, when there is a large amount of EVOH resin particles, 100 EVOH resin particles can be first selected and their individual ethylene contents determined using the above-mentioned ethylene content analysis method. Next, particles with an ethylene content of 35 to 48 mol% are pre-classified as low-melting-point EVOH resin particles with a melting point of approximately 135 to 179°C, and particles with an ethylene content of 24 to 34 mol% are pre-classified as high-melting-point EVOH resin particles with a melting point of approximately 180 to 198°C. Furthermore, 10 EVOH resin particles are randomly selected from the group of low-melting-point EVOH resin particles and high-melting-point EVOH resin particles, and their surface roughness is determined using the above-mentioned surface parameter measurement method. The melting points of the EVOH resin particles are then confirmed using the above-mentioned melting point measurement method.

[0086] Preparation and analysis of EVOH monolayer films The EVOH resin particle compositions of Examples 1 to 5 and Comparative Examples 1 to 6 were formed into films by the following method. The EVOH resin particle compositions of Examples 1 to 5 and Comparative Examples 1 to 6 were fed into a single-screw extruder (model: ME25 / 5800V4, brand: OCS) and extruded to produce single-layer films. The thickness of the films made of the EVOH resin particle compositions of Examples 1 to 5 and Comparative Examples 1 to 6 was 20 μm each. The extruder temperature was set to 220°C, and the screw rotation speed was set to 7 rpm (rotations / minutes).

[0087] Processability analysis of EVOH films: Measurement and evaluation of gel particles (gels) The gel particles in the EVOH film were measured and analyzed using an FSA-100 designed with a charge-coupled device (CCD) sensor and FSA-100 V.8 software. The evaluation method was as follows: if the gel particle size was <100 μm and the number was <450, it was indicated as "best" (○); if the number was 450-1000, it was indicated as "fair" (△); and if the number was >1000, it was indicated as poor (X). If the gel particle size was 100-200 μm and the number was <50, it was indicated as "best" (○); if the number was 50-100, it was indicated as fair (△); and if the number was >100, it was indicated as poor (X). If the gel particle size was >200 μm and the number was <10, it was indicated as "best" (○); if the number was 10-20, it was indicated as fair (△); and if the number was >20, it was indicated as poor (X).

[0088] Mechanical property analysis of EVOH film: Measurement and evaluation of film tensile elongation Here, a 180 μm-thick monolayer film was produced using the single-screw extruder and cut into a 30 mm MD x 90 mm TD (transverse direction, or TD, where MD stands for machine direction). After 30 minutes at 130°C, the film was measured in both the MD and TD directions at a tensile speed of 1000 mm / min according to ASTM D882. As used herein, "tensile elongation (%)" is defined as [(stretched length - pre-stretched length) / pre-stretched length] x 100%. The evaluation method was as follows: if the film sample exhibited a tensile elongation value of over 1000%, it was considered excellent and indicated by a "○"; if the film sample exhibited a tensile elongation value of 800-1000%, it was considered fair and indicated by a "△"; and if the film sample exhibited a tensile elongation value of less than 800%, it was considered poor and indicated by an "X."

[0089] Fabrication of multilayer structures Here, the EVOH resin particle compositions of Examples 1 to 5 and Comparative Examples 1 to 6, polypropylene, and a tie layer (e.g., OREVAC (registered trademark) 18729, Arkema Inc.) were co-extruded to form individual multilayer films of Examples 1 to 5 and Comparative Examples 1 to 6. The multilayer films had five layers. Specifically, EVOH particles (I), polypropylene (II), and adhesive resin (III) were each fed into a five-layer co-extrusion film molding machine to produce a multilayer sheet with the following structure: (II) / (III) / (I) / (III) / (II), with thicknesses of 300 / 25 / 50 / 25 / 300 (μm), respectively.

[0090] Analysis of results of Examples and Comparative Examples Here, the EVOH resin particle compositions of Examples 1 to 5 and Comparative Examples 1 to 6 were compared with each other in terms of gel particles and tensile elongation of films produced therefrom. Specific data are shown in Tables 1 and 2, respectively.

[0091] [Table 1]

[0092] [Table 2]

[0093] As can be seen from Tables 1 and 2, the effective volume (Vmp) of the surface peaks of the first EVOH resin particles contained in the EVOH resin particle compositions of Examples 1 to 5 is 0.00001 to 6 μm 3 / μm 2 The actual volume (Vmp) of the surface peak of the second EVOH resin particle is 0.00015 to 2 μm 3 / μm 2Therefore, films made from these particles exhibit good performance in both gel particle size and tensile elongation. The films inherently possess excellent processability and mechanical properties. In contrast, the EVOH resin particle compositions of Comparative Examples 1 to 6 did not satisfy the ranges for the surface peak volume (Vmp) of the first and second EVOH resin particles, and therefore the films produced did not have ideal processability or mechanical properties. Preferably, the Vmp of the second EVOH resin particles of the present invention is higher than that of the first EVOH resin particles. Preferably, the melting point of the first EVOH resin particles was 135 to 179°C, and the melting point of the second EVOH resin particles was 180 to 198°C. Preferably, the ethylene content of the first EVOH resin particles was 36 to 50 mol%, and the ethylene content of the second EVOH resin particles was 20 to 35 mol%.

[0094] Furthermore, as can be seen from a comparison of Tables 1 and 2, the first EVOH resin particles contained in the EVOH resin particle composition of Comparative Example 4, the second EVOH resin particles contained in the EVOH resin particle composition of Comparative Example 5, and the second EVOH resin particles contained in the EVOH resin particle composition of Comparative Example 6 each fall within the Vmp range of the first or second EVOH resin particles specified in the present invention, but the other EVOH resin particles contained in the EVOH resin particle composition do not fall within the corresponding Vmp range. This shows that only when the two types of EVOH resin particles contained in an EVOH resin particle composition satisfy the Vmp range specified in the present application can the two types of EVOH resins be mixed together to produce a film with more ideal processability and mechanical properties.

[0095] The inventors have found that the desired surface peak volume (Vmp) of the present invention can be further controlled by adjusting the process parameters of the centrifugation and washing steps during processing of EVOH resin particles. Specifically, without being bound by any particular theory, excessively high rotation speed of the dehydrator, a low water / wet particle ratio during pumping, a high rotation speed of the pump when a closed centrifugal pump is used, or a high water flow rate during washing can increase the surface peak volume of EVOH resin particles to some extent. Conversely, excessively low rotation speed of the dehydrator, a high water / wet particle ratio during pumping, a low rotation speed of the pump when an open centrifugal pump is used, or a low water flow rate can decrease the surface peak volume of EVOH resin particles to some extent. In a specific embodiment, the rotation speed of the dehydrator is preferably controlled to 1000 to 5000 rpm, the water / wet particle ratio during pumping is preferably controlled to 3 to 10, when a closed centrifugal pump is used for pumping, the rotation speed of the pump is preferably 5000 rpm or less, and when an open centrifugal pump is used for pumping, the rotation speed of the pump is preferably 1000 rpm or more, the water flow rate during water washing is 2 to 7 m / min, and the rotation speed of the second dehydrator is preferably controlled to 1000 to 4000 rpm, thereby enabling the desired solid volume of the surface peaks of the EVOH resin particles to be obtained.

[0096] All ranges provided herein are intended to include each specific range within the stated range and combinations of subranges between the stated ranges. Also, any range explicitly stated herein includes its endpoints unless otherwise specified. Thus, the range 1 to 5 specifically includes 1, 2, 3, 4, and 5, as well as subranges such as 2 to 5, 3 to 5, 2 to 3, 2 to 4, and 1 to 4.

[0097] All publications and patent applications cited in this specification are hereby incorporated by reference and for all purposes are specifically and individually indicated to be incorporated by reference. In the event of a conflict between the present specification and a publication or patent application incorporated by reference herein, the present specification will control.

[0098] As used herein, the terms "comprise," "have," and "include" have an open-ended, non-limiting meaning. The terms "a," "an," and "the" may be intended to include the plural as well, unless the context clearly dictates otherwise. The term "one or more" means "at least one" and can therefore include a single feature or a mixture / combination. The term "between" is inclusive of the two endpoint values.

[0099] Other than in the examples provided herein, or unless otherwise specified, all numerical values ​​expressing amounts of ingredients and / or reaction conditions can be modified in all instances by the term "about," which means within ±5% of the stated numerical value. As used herein, the terms "essentially free" or "substantially free" mean less than about 2% of a particular characteristic. Any element or feature explicitly recited herein can be negatively excluded from the claims.

Claims

1. 0.00001~6μm ３ / μm ２ a first EVOH resin particle having a surface peak portion having a substantial volume (Vmp) of 0.00015~20μm ３ / μm ２ and second EVOH resin particles having a surface peak portion substantial volume (Vmp) of Including, The ethylene-vinyl alcohol copolymer (EVOH) resin particle composition has a melting point of 135 to 179°C for the first EVOH resin particles and a melting point of 180 to 198°C for the second EVOH resin particles.

2. The Vmp of the second EVOH resin particles is greater than the Vmp of the first EVOH resin particles. The EVOH resin particle composition according to claim 1 .

3. 3. The EVOH resin particle composition according to claim 1, wherein the ethylene content of the first EVOH resin particles is 36 to 50 mole percent.

4. 3. The EVOH resin particle composition according to claim 1, wherein the second EVOH resin particles have an ethylene content of 20 to 35 mol percent.

5. 3. The EVOH resin particle composition according to claim 1, wherein the EVOH resin particles have a shape of a cylinder, an elliptical cylinder, a rectangular cylinder, a sphere, an oval sphere, or a go stone, and the ratio of the major axis to the height is 1 to 5 mm, and the minor axis is 1 to 5 mm.

6. 3. The EVOH resin particle composition according to claim 1, wherein the weight percentage of the first EVOH resin particles to the second EVOH resin particles is 5:95 to 75:

25.

7. 3. The EVOH resin particle composition according to claim 1, wherein the EVOH resin particle composition has a boron content of 5 to 550 ppm.

8. 3. The EVOH resin particle composition according to claim 1, wherein the EVOH resin particle composition has an alkali metal content of 10 to 550 ppm.

9. 3. The EVOH resin particle composition according to claim 1, wherein the first EVOH resin particles have a surface parameter of kurtosis (Sku) of 0.0020 to 25, and the second EVOH resin particles have a surface parameter of kurtosis (Sku) of 0.0070 to 111.

10. 3. The EVOH resin particle composition according to claim 1, wherein the first EVOH resin particles have a surface parameter of a maximum peak height (Sp) of a face of 0.0005 to 29 μm, and the second EVOH resin particles have a surface parameter of a maximum peak height (Sp) of a face of 0.0020 to 63 μm.

11. 3. The EVOH resin particle composition according to claim 1, wherein the first EVOH resin particles have a surface parameter of a peak height (Spk) of 0.001 to 2 μm, and the second EVOH resin particles have a surface parameter of a peak height (Spk) of 0.003 to 22 μm.

12. 3. The EVOH resin particle composition according to claim 1, wherein the first EVOH resin particles have a surface parameter of a pole height (Sxp) of 0.001 to 12 μm, and the second EVOH resin particles have a surface parameter of a pole height (Sxp) of 0.002 to 48 μm.

13. 3. The EVOH resin particle composition according to claim 1, wherein the first EVOH resin particles have a surface parameter of arithmetic mean line height (Ra) of 0.001 to 0.990 μm, and the second EVOH resin particles have a surface parameter of arithmetic mean line height (Ra) of 0.001 to 0.990 μm.

14. 3. The EVOH resin particle composition according to claim 1, wherein the first EVOH resin particles have a surface parameter of maximum line height (Rz) of 0.0010 to 9.9000 μm, and the second EVOH resin particles have a surface parameter of maximum line height (Rz) of 0.0010 to 9.9000 μm.

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