TWI761235B - Ethylene vinyl alcohol copolymer resin composition, ethylene vinyl alcohol copolymer film formed therefrom, as well as multilayer structure containing the same - Google Patents

Abstract

The instant disclosure relates to an ethylene vinyl alcohol copolymer (EVOH) resin composition, an EVOH film formed therefrom, and a multilayer structure containing the same. The surface roughness of the EVOH resin composition is the root mean square gradient (Sdq) between 0.0005 and 13. The EVOH of the present invention can reduce the torque output during processing, and make the appearance of the EVOH film with highly uniform.

Description

Ethylene-vinyl alcohol copolymer resin composition, ethylene-vinyl alcohol copolymer film formed therefrom, and multilayer structure comprising the same

The present invention relates to an ethylene-vinyl alcohol (EVOH) resin composition. The ethylene-vinyl alcohol copolymer resin composition has high surface uniformity, especially the root mean square slope (Sdq) of the surface roughness ranging from 0.0005 to 13. The present invention also discloses a film formed from the EVOH resin composition and a multilayer structure comprising the EVOH resin composition.

EVOH resins are widely used in multilayer bodies for the preservation of perishable items. For example, EVOH resins and multilayers are commonly used in the food packaging industry, the medical device and consumables industry, the pharmaceutical industry, the electronics industry, and the agrochemical industry. EVOH resins are commonly used in multilayer bodies as a unique layer to act as an oxygen barrier.

At present, it is known that EVOH particles formed from EVOH resin have large surface roughness and high friction between particles, resulting in extremely high torque during EVOH processing. Although the processability of EVOH has been adjusted by adding lubricants in the past, there is still a need for further improvement.

There is a continuing need for EVOH resins that provide reduced torque output during processing and achieve high surface uniformity.

The present invention relates to an ethylene-vinyl alcohol copolymer (EVOH) resin composition having a surface with a root mean square slope (Sdq) ranging from 0.0005 to 13 in roughness. In addition, the surface roughness of the EVOH resin composition may further be between 0.05 to 110% of the interface development ratio (Sdr), between 0.003 to 1.5 μm of the surface arithmetic mean height (Sa) and/or between 0.005 to 0.005 μm. The maximum trough depth (Sv) on the surface of 8 μm; wherein the ethylene-vinyl alcohol copolymer resin composition includes an ethylene-vinyl alcohol copolymer resin. The EVOH resin composition can be in the form of particles, films, fibers, and the like. The EVOH resin composition can be used to make films or multilayer structures. The inventors found that by controlling the surface roughness of EVOH particles, the torque output during EVOH processing can be reduced, and the surfaces of films formed from the EVOH resin composition and multilayer structures comprising the EVOH resin composition can exhibit a high degree of uniformity.

Further, the EVOH resin composition is in the form of particles.

Further, the ethylene content of the EVOH in the EVOH resin composition is between 20-48 mole percent.

Further, the degree of saponification of the EVOH in the EVOH resin composition is greater than 99.5 mole percent.

Further, the maximum height (Rz) of the surface of the EVOH resin composition is between 0.02 and 15 μm.

Further, the maximum height (Rz) of the surface of the EVOH resin composition is between 0.02 and 9.9 μm.

Further, the water content of the EVOH resin composition is less than or equal to 1 weight percent.

Further, the EVOH resin composition includes two or more ethylene-vinyl alcohol copolymers with different ethylene contents.

Further, the EVOH resin composition has a boron content of 5-550 ppm.

Further, the EVOH resin composition has an alkali metal content of 5-550 ppm.

Further, the EVOH resin composition further comprises one or a combination of the group consisting of cinnamic acid, conjugated polyene, slip agent and alkaline earth metal.

In another aspect of the present invention, there is provided an ethylene-vinyl alcohol copolymer film formed from the above EVOH resin composition.

Further, the multi-layer structure includes: (a) at least one layer formed of the ethylene-vinyl alcohol copolymer resin as described above; (b) at least one polymer layer; and (c) at least one adhesive layer.

Further, the multi-layer structure, wherein 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.

The present invention relates to an ethylene-vinyl alcohol copolymer (EVOH) resin composition, wherein the ethylene-vinyl alcohol copolymer resin composition comprises an ethylene-vinyl alcohol copolymer resin. The EVOH resin composition has low surface roughness, especially the surface roughness is between 0.0005 and 13 with a root mean square slope (Sdq). In addition, the surface roughness of the EVOH resin composition may further be between 0.05 to 110% of the interface development ratio (Sdr), between 0.003 to 1.5 μm of the surface arithmetic mean height (Sa) and/or between 0.005 to 0.005 μm. Maximum trough depth (Sv) on the surface of 8μm. In a preferred embodiment, the Sdq on the surface of the EVOH resin composition is from 0.001 to 10; wherein, the surface of the EVOH resin composition is further selected from the group consisting of Sdr ranging from 0.1 to 100%, Sa ranging from 0.005 to 0.95 μm and The roughness of one or a combination of the group consisting of Sv ranging from 0.01 to 5 μm.

The control of the surface roughness of the EVOH resin composition can be achieved by controlling the conveying method in the EVOH process, so that the EVOH resin composition and its film have good efficacy. The EVOH resin composition can be used to make films or multilayer structures. The inventors found that by controlling the surface roughness parameter Sdq of EVOH particles in a specific range, the torque output during EVOH processing can be reduced, and the gel formation of films and multilayer structures formed therefrom can be improved, and the surface of EVOH particles can be highly uniformity.

The definition of the root mean square slope (Sdq) refers to ISO 25178:2012, which refers to the parameter calculated from the root mean square of the slope of all points within the defined range. The surface roughness Sdq is preferably between 0.0005 and 13, and the Sdq can be, for example, between 0.0005 and 13, between 0.0005 and 12, between 0.0005 and 11, between 0.0005 and 10, between 0.0005 to 9, 0.0005 to 8, 0.0005 to 7, 0.0005 to 6, 0.0005 to 5, 0.0005 to 4, 0.0005 to 3, 0.0005 to 2, 0.0005 to 1 , between 0.0005 and 0.1, between 0.0005 and 0.01, between 0.0005 and 0.001, between 0.001 and 13, between 0.001 and 12, between 0.001 and 11, between 0.001 and 10, between 0.001 and 9, between at 0.001-8, between 0.001-7, between 0.001-6, between 0.001-5, between 0.001-4, between 0.001-3, between 0.001-2, between 0.001-1, between 0.001 to 0.1, from 0.001 to 0.01, from 0.05 to 13, from 0.05 to 12, from 0.05 to 11, from 0.05 to 10, from 0.05 to 9, from 0.05 to 8, from 0.05 to 7 , between 0.05 and 6, between 0.05 and 5, between 0.05 and 4, between 0.05 and 3, between 0.05 and 2, between 0.05 and 1, between 0.05 and 0.1, between 0.1 and 13, between at 0.1-12, between 0.1-11, between 0.1-10, between 0.1-9, between 0.1-8, between 0.1-7, between 0.1-6, between 0.1-5, between 0.1 to 4, from 0.1 to 3, from 0.1 to 2, from 1 to 13, from 1 to 12, from 1 to 11, from 1 to 10, from 1 to 9, from 1 to 8 , between 1-7, between 1-6, between 1-5, between 1-4, between 1-3, between 3-13, between 3-12, between 3-11, between on 3 to 10, between 3 and 9, between 3 and 8, between 3 and 7, between 3 and 6, between 3 and 5, between 5 and 13, between 5 and 12, between 5 to 11, between 5 and 10, between 5 and 9, between 5 and 8, between 5 and 7, between 7 and 13, between 7 and 12, between 7 and 11, between 7 and 10 , between 7 and 9, between 7 and 8, between 9 and 13, between 9 and 12, between 9 and 11, or between 9 and 10.

The interface development ratio (Sdr) is defined with reference to ISO 25178:2012, and refers to the ratio of the area (surface area) of the defined range developed relative to the area of the defined range. The surface roughness Sdr is preferably between 0.05 and 110%, and the Sdr can be, for example, between 0.05 and 110%, between 0.05 and 100%, between 0.05 and 90%, between 0.05 and 80%. %, 0.05-70%, 0.05-60%, 0.05-50%, 0.05-40%, 0.05-30%, 0.05-20%, 0.05-10% , between 0.05 and 1%, between 0.05 and 0.1%, between 0.1 and 110%, between 0.1 and 100%, between 0.1 and 90%, between 0.1 and 80%, between 0.1 and 70%, 0.1 to 60%, 0.1 to 50%, 0.1 to 40%, 0.1 to 30%, 0.1 to 20%, 0.1 to 10%, 0.1 to 1%, between Between 1 and 110%, between 1 and 100%, between 1 and 90%, between 1 and 80%, between 1 and 70%, between 1 and 60%, between 1 and 50%, between 1 to 40%, 1 to 30%, 1 to 20%, 1 to 10%, 10 to 110%, 10 to 100%, 10 to 90%, 10 to 80%, between 10 and 70%, between 10 and 60%, between 10 and 50%, between 10 and 40%, between 10 and 30%, between 10 and 20%, between 30 and 110%, 30-100%, 30-90%, 30-80%, 30-70%, 30-60%, 30-50%, 50-110 %, between 50 and 100%, between 50 and 90%, between 50 and 80%, between 50 and 70%, between 50 and 60%, between 70 and 110%, between 70 and 100% , between 70 and 90%, between 90 and 110%, between 90 and 100%.

The surface arithmetic mean height (Sa) is the arithmetic mean height of the surface, which is defined with reference to ISO 25178:2012, which means the mean surface relative to the surface and the absolute value average of the height difference of each point. The roughness Sa of the surface is preferably between 0.003 and 1.5 μm, and the Sa can be, for example, between 0.003 and 1.5 μm, between 0.003 and 1.3 μm, between 0.003 and 1.1 μm, between 0.003 and 0.9 μm, between 0.003 and 0.7μm, between 0.003 and 0.5μm, between 0.003 and 0.3μm, between 0.003 and 0.1μm, between 0.003 and 0.09μm, between 0.003 and 0.07μm, between 0.003 and 0.05μm , between 0.003 and 0.03μm, between 0.003 and 0.01μm, between 0.003 and 0.009μm, between 0.003 and 0.007μm, between 0.003 and 0.005μm, between 0.005 and 1.5μm, between 0.005 and 1.3μm, 0.005 to 1.1 μm, 0.005 to 0.9 μm, 0.005 to 0.7 μm, 0.005 to 0.5 μm, 0.005 to 0.3 μm, 0.005 to 0.1 μm, 0.005 to 0.09 μm, at 0.005-0.07μm, between 0.005-0.05μm, between 0.005-0.03μm, between 0.01-1.5μm, between 0.01-1.3μm, between 0.01-1.1μm, between 0.01-0.9μm, between 0.01 to 0.7 μm, 0.01 to 0.5 μm, 0.01 to 0.3 μm, 0.01 to 0.1 μm, 0.01 to 0.09 μm, 0.01 to 0.07 μm, 0.01 to 0.05 μm, 0.01 to 0.03µm, 0.03 to 1.5µm, 0.03 to 1.3µm, 0.03 to 1.1µm, 0.03 to 0.9µm, 0.03 to 0.7µm, 0.03 to 0.5µm, 0.03 to 0.03µm 0.3μm, between 0.03 and 0.1μm, between 0.03 and 0.09μm, between 0.03 and 0.07μm, between 0.03 and 0.05μm, between 0.05 and 1.5μm, between 0.05 and 1.3μm, between 0.05 and 1.1 μm, between 0.05 and 0.9μm, between 0.05 and 0.7μm, between 0.05 and 0.5μm, between 0.05 and 0.3μm, between 0.05 and 0.1μm, between 0.05 and 0.09μm, between 0.07 and 1.5μm , between 0.07-1.3μm, between 0.07-1.1μm, between 0.07-0.9μm, between 0.07-0.7μm, between 0.07-0.5μm, between 0.07-0.3μm, between 0.07-0.1μm, Between 0.07 to 0.09μm, between 0.1 to 1.5μm, between 0.1 to 1.3 μm, 0.1 to 1.1 μm, 0.1 to 0.9 μm, 0.1 to 0.7 μm, 0.1 to 0.5 μm, 0.3 to 1.5 μm, 0.3 to 1.3 μm, 0.3 to 1.1 μm, 0.3 to 0.9 μm, 0.3 to 0.7 μm, 0.3 to 0.5 μm, 0.5 to 1.5 μm, 0.5 to 1.3 μm, 0.5 to 1.1 μm, 0.5 to 0.5 μm 0.9μm, between 0.7 and 1.5μm, between 0.7 and 1.3μm, between 0.7 and 1.1μm, between 0.7 and 0.9μm, between 0.9 and 1.5μm, between 0.9 and 1.3μm, or between 0.9 and 1.1 μm.

The maximum trough depth (Sv) of the surface is the maximum trough depth of the surface, which is defined with reference to ISO 25178:2012, and is the absolute value of the height of the lowest point in the defined range. The roughness Sv of the surface is preferably between 0.005 and 8 μm, and the Sv can be, for example, between 0.005 and 8 μm, between 0.005 and 7 μm, between 0.005 and 6 μm, between 0.005 and 5 μm, between 0.005 to 4μm, between 0.005 and 3μm, between 0.005 and 2μm, between 0.005 and 1μm, between 0.005 and 0.1μm, between 0.005 and 0.01μm, between 0.01 and 8μm, between 0.01 and 7μm, between 0.01 to 6μm, 0.01 to 5μm, 0.01 to 4μm, 0.01 to 3μm, 0.01 to 2μm, 0.01 to 1μm, 0.01 to 0.1μm, 0.1 to 8μm, 0.1 to 0.1μm 7μm, between 0.1 and 6μm, between 0.1 and 5μm, between 0.1 and 4μm, between 0.1 and 3μm, between 0.1 and 2μm, between 0.1 and 1μm, between 0.4 and 8μm, between 0.4 and 7μm, 0.4-6μm, 0.4-5μm, 0.4-4μm, 0.4-3μm, 0.4-2μm, 0.4-1μm, 0.8-8μm, 0.8-7μm, between 0.8-6μm, 0.8-5μm, 0.8-4μm, 0.8-3μm, 0.8-2μm, 0.8-1μm, 1-8μm, 1-7μm, 1- 6μm, between 1 and 5μm, between 1 and 4μm, between 1 and 3μm, between 1 and 2μm, between 2 and 8μm, between 2 and 7μm, between 2 and 6μm, between 2 and 5μm, 2-4μm, 3-8μm, 3-7μm, 3-6μm, 3-5μm, 3-4μm, 4-8μm, 4-7μm, between 4 to 6 μm, between 4 and 5 μm, between 5 and 8 μm, between 5 and 7 μm, or between 5 and 6 μm.

In one aspect, the present invention provides an EVOH resin composition. The EVOH resin composition can be in the form of particles, films, fibers, and the like. As used herein, EVOH particles refer to the form and/or shape of an EVOH resin composition that has been pelletized to form one or more particles. Although the EVOH resin composition is described throughout this disclosure as pelletized to form one or more EVOH pellets, the EVOH resin composition can be processed into the form of beads, cubes, chips, shavings, and the like. In some embodiments, the EVOH resin composition is in the form of particles, and the so-called particle form can be columnar, round or flat. The round particle shape can be spherical, elliptical spherical or chess shape, and the columnar shape can be cylindrical, elliptical columnar or angular columnar shape.

When the EVOH particles are spherical, elliptical, or chess-shaped, the largest outer diameter of the particles is taken as the long side, and the largest diameter in the cross-section with the largest area in the cross-section perpendicular to the long side is taken as the short side. The range of its long side can be between 1.5~5.0 mm, 2.2~5.0 mm, 2.4~5.0 mm, 2.6~5.0 mm, 2.8~5.0 mm, 3.0~5.0 mm, 3.2~5.0 mm, 3.4~5.0 mm, 3.6 mm ~5.0 mm, 3.8~5.0 mm, 4.0~5.0 mm, 2.0~4.5 mm, 2.0~4.4 mm, 2.0~4.2 mm, 2.0~4.0 mm, 2.0~3.8 mm, 2.0~3.6 mm, 2.0~3.4 mm, 2.0 ~3.2 mm, 2.0~3.0 mm; the range of its short side can be between 1.5~5.0 mm, 1.8~4.6 mm, 2.4~4.6 mm, 2.6~4.6 mm, 2.8~4.6 mm, 3.0~4.6 mm, 3.2~ 4.6 mm, 3.4~4.6 mm, 3.6~4.6 mm, 3.8~4.6 mm, 4.0~4.6 mm, 1.6~4.5 mm, 1.6~4.4 mm, 1.6~4.2 mm, 1.6~4.0 mm, 1.6~3.8 mm, 1.6~ 3.6 mm, 1.6~3.4 mm, 1.6~3.2 mm, 1.6~3.0 mm.

When EVOH particles are cylindrical or elliptical, their heights can range from 1.5~5.0 mm, 1.7~5.0 mm, 2.2~5.0 mm, 2.4~5.0 mm, 2.6~5.0 mm, 2.8~5.0 mm, 3.0~5.0 mm, 3.2~5.0 mm, 3.4~5.0 mm, 3.6~5.0 mm, 3.8~5.0 mm, 4.0~5.0 mm, 1.7~4.5 mm, 1.7~4.4 mm, 1.7~4.2 mm, 1.7~4.0 mm, 1.7~3.8 mm, 1.7~3.6 mm, 1.7~3.4 mm, 1.7~3.2 mm, 1.7~3.0 mm; the long axis range of its cross-sectional area can be between 1.5~5.0 mm, 1.7~5.0 mm, 2.2~5.0 mm , 2.4~5.0 mm, 2.6~5.0 mm, 2.8~5.0 mm, 3.0~5.0 mm, 3.2~5.0 mm, 3.4~5.0 mm, 3.6~5.0 mm, 3.8~5.0 mm, 4.0~5.0 mm, 1.7~4.5 mm , 1.7~4.4 mm, 1.7~4.2 mm, 1.7~4.0 mm, 1.7~3.8 mm, 1.7~3.6 mm, 1.7~3.4 mm, 1.7~3.2 mm, 1.7~3.0 mm.

The surface roughness characteristics of the EVOH resin composition can also be described by the maximum height (Rz) of the surface line. The sum of the height of the crest and the depth of the deepest trough.

In one embodiment, the Rz of the surface of the EVOH resin composition may be between about 0.02-15 μm, for example: between 0.02-15 μm, between 0.02-13 μm, between 0.02-11 μm, between 0.02~9 μm, 0.02~7 μm, 0.02~5 μm, 0.02~3 μm, 0.02~1 μm, 0.02~0.9 μm, 0.02~0.7 μm, 0.02 ~0.5 μm, 0.02~0.1 μm, 0.1~15 μm, 0.1~13 μm, 0.1~11 μm, 0.1~9 μm, 0.1~7 μm, 0.1~ 5 μm, 0.1~3 μm, 0.1~1 μm, 0.1~0.9 μm, 0.1~0.7 μm, 0.5~15 μm, 0.5~13 μm, 0.5~11 μm, 0.5~9 μm, 0.5~7 μm, 0.5~5 μm, 0.5~3 μm, 0.5~1 μm, 0.5~0.9 μm, 0.5~0.7 μm , between 0.8~15 μm, between 0.8~13 μm, between 0.8~11 μm, between 0.8~9 μm, between 0.8~7 μm, between 0.8~5 μm, between 0.8~3 μm, Between 0.8~1 μm, between 1~15 μm, between 1~13 μm, between 1~11 μm, between 1~9 μm, between 1~7 μm, between 1~5 μm, between at 1~3 μm, between 3~15 μm, between 3~13 μm, between 3~11 μm, between 3~9 μm, between 3~7 μm, between 3~5 μm, between 5~15 μm, 5~13 μm, 5~11 μm, 5~9 μm, 5~7 μm, 7~15 μm, 7~13 μm, 7 ~11 μm, between 7-9 μm, between 9-15 μm, between 9-13 μm, between 9-11 μm or between 11-15 μm. In a preferred embodiment, the Rz of the surface is between 0.02 and 9.9 μm.

The EVOH particles are formed from an EVOH having an ethylene content. For example, the ethylene content of the EVOH may be about 20 to about 48 mole%, about 20 to about 45 mole%, about 25 to about 45 mole%, about 28 to about 42 mole%, or about 30 to about 40 mole%. The EVOH resin composition system may be formed from two or more EVOHs having different ethylene contents. For example, one of the EVOHs may have an ethylene content in the range of about 20 to about 35 mole%, such as about 24 to about 35 mole%, about 28 to about 35 mole%, about 20 to about 32 mole%, about 24 to about 24 mole% About 32 mole%, about 28 to about 32 mole%, about 20 to about 30 mole%, or about 24 to about 30 mole%. Additionally/alternatively, one of the EVOHs may have an ethylene content in the range of about 36 to about 48 mole%, such as about 40 to about 48 mole%, about 44 to about 48 mole%, about 36 to about 45 mole%, or about 40 to about 45 mole%. However, in some preferred embodiments, the EVOH resin composition is formed from a single EVOH having an ethylene content of about 20 to about 48 mole %.

In addition/alternatively, the degree of saponification of the EVOH in the EVOH resin composition may be 90 mole% or higher, preferably 95 mole% or higher, preferably 97 mole% or higher, preferably 99.5 mole% or higher.

The EVOH resin composition may in some cases comprise boron compounds and/or boric acid and/or cinnamic acid and/or alkali metals and/or conjugated polyenes and/or lubricants and/or alkaline earth metals, salts thereof and/or or a mixture thereof. The above substances can impart better properties to the EVOH resin composition.

In another aspect of the present invention, there is provided an EVOH resin composition (or particles thereof) which may comprise an ethylene-vinyl alcohol copolymer; and a boron compound, wherein the boron content of the ethylene-vinyl alcohol copolymer resin composition is between About 5-550 ppm. In some cases, the boron content of the EVOH resin composition, based on the total weight of the EVOH resin composition, may be: between about 5-550 ppm, between about 5-500 ppm, between about 5-450 ppm, between at about 5-400 ppm, between about 5-350 ppm, between about 5-300 ppm, between about 5-250 ppm, between about 5-200 ppm, between about 5-150 ppm, between about 5-100 ppm, between about 5-50 ppm, between about 10-550 ppm, between about 10-500 ppm, between about 10-450 ppm, between about 10-400 ppm, between about 10- 350 ppm, between about 10-300 ppm, between about 10-250 ppm, between about 10-200 ppm, between about 10-150 ppm, between about 10-100 ppm, between about 10-50 ppm , between about 50-550 ppm, between about 50-500 ppm, between about 50-450 ppm, between about 50-400 ppm, between about 50-350 ppm, between about 50-300 ppm, between about at 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 100-400 ppm, between about 100-350 ppm, between about 100-300 ppm, between about 100-250 ppm, between about 100-200 ppm, between about 100- 150 ppm, between about 200-550 ppm, between about 200-500 ppm, between about 200-450 ppm, between about 200-400 ppm, between about 200-350 ppm, between about 200-300 ppm , between about 200-250 ppm, between about 300-550 ppm, between about 300-500 ppm, between about 300-450 ppm, between about 300-400 ppm, between about 300-350 ppm, between about At about 400-550 ppm, between about 400-500 ppm, between about 400-450 ppm, or between about 500-550 ppm. Without being bound by any particular theory, it is believed that adding a boron compound to the EVOH resin composition to a boron content of 5 to 550 ppm in EVOH reduces or eliminates sticking of the EVOH resin composition during extrusion through the screw extruder , and further improve the uniformity and flexibility of film thickness. In some cases, such EVOH resin compositions can clean the screw extruder during extrusion by removing or at least partially removing EVOH resin previously adhering to the interior surfaces of the screw extruder, thereby allowing the material With self-cleaning function, it can further improve the uniformity of film thickness.

In some cases, the boron compound may include boric acid or a metal salt thereof. Examples of metal salts include, but are not limited to, calcium borate, cobalt borate, zinc borate (eg, zinc tetraborate, zinc metaborate), potassium aluminum borate, ammonium borate (eg, ammonium metaborate, ammonium tetraborate, ammonium pentaborate, ammonium octaborate) ), cadmium borate (such as cadmium orthoborate, cadmium tetraborate), potassium borate (such as potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, potassium octaborate), silver borate (such as silver metaborate, tetraborate silver), 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, sodium octaborate) , Lead borate (such as lead metaborate, lead hexaborate), nickel borate (such as nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate), barium borate (such as barium orthoborate, barium metaborate, barium diborate) , barium tetraborate), bismuth borate, magnesium borate (such as magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate), manganese borate (such as manganese (I) borate, manganese metaborate, manganese tetraborate), lithium borate (eg, lithium metaborate, lithium tetraborate, lithium pentaborate), salts thereof, or combinations thereof. Borate minerals may be included, such as borax, kaleite, brookite, boronite, borate/suanite, and szaibelyite. Among them, borax, boric acid and sodium borate (eg, sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, and sodium octaborate) are preferably used.

In some cases, the EVOH resin composition may also contain an alkali metal. The alkali metal source for containing the above-mentioned alkali metal in the EVOH resin composition of the present invention includes alkali metal compounds such as alkali metal salts, alkali metal oxides, and alkali metal hydroxides. Among them, alkali metal salts are preferred. Examples of alkali metal salts include carbonates, bicarbonates, phosphates, borates, sulfates, chlorides, acetates, butyrates, propionates, heptanoates, and caprates of alkali metals. , malonate, succinate, adipate, suberate, sebacate, etc. These can be used alone or in combination of two or more.

The alkali metals used in the invention include lithium, sodium, potassium, rubidium, and cesium. These can be used alone or in combination of two or more. Among them, sodium and potassium are preferred, and sodium is particularly preferred.

The EVOH resin composition may have an alkali metal content of about 5-550 ppm, and the alkali metal content may be, for example: between 5-550 ppm, between about 5-500 ppm, between about 5-450 ppm , between about 5-400 ppm, between about 5-350 ppm, between about 5-300 ppm, between about 5-250 ppm, between about 5-200 ppm, between about 5-150 ppm, between about at about 5-100 ppm, between about 5-50 ppm, between about 10-550 ppm, between about 10-500 ppm, between about 10-450 ppm, between about 10-400 ppm, between about 10 -350 ppm, between about 10-300 ppm, between about 10-250 ppm, between about 10-200 ppm, between about 10-150 ppm, between about 10-100 ppm, between about 10-50 ppm, between about 50-550 ppm, between about 50-500 ppm, between about 50-450 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 100-400 ppm, between about 100-350 ppm, between about 100-300 ppm, between about 100-250 ppm, between about 100-200 ppm, between about 100 -150 ppm, between about 200-550 ppm, between about 200-500 ppm, between about 200-450 ppm, between about 200-400 ppm, between about 200-350 ppm, between about 200-300 ppm, between about 200-250 ppm, between about 300-550 ppm, between about 300-500 ppm, between about 300-450 ppm, between about 300-400 ppm, between about 300-350 ppm, Between about 400-550 ppm, between about 400-500 ppm, between about 400-450 ppm, or between about 500-550 ppm.

In addition/alternatively, the EVOH resin composition may further comprise one or a combination of the group consisting of cinnamic acid, conjugated polyene, slip agent and alkaline earth metal, or a salt thereof and/or a mixture thereof. The above-mentioned substances are common substances that are usually present in EVOH resin compositions to give them better properties. When the content of the compound having the conjugated polyene structure is 1 to 30,000 ppm per unit weight of the EVOH resin composition, coloration after heating can be further suppressed, and thermal stability is further improved. On the other hand, if the content of the alkali metal compound or alkaline earth metal compound contained in the above-mentioned EVOH resin composition is 1 to 1000 ppm in terms of metal conversion per unit weight of the EVOH resin composition, the long-term running formability can be achieved. better.

The conjugated polyenes are such as but not limited to: isoprene, 2,3-dimethyl-1,3-butadiene, 2-tert-butyl-1,3-butadiene, 1,3- Pentadiene, 2,4-dimethyl-1,3-pentadiene, 3,4-dimethyl-1,3-pentadiene, 3-ethyl-1,3-pentadiene, 2 -Methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 1,3-hexadiene, 2,5-dimethyl-2,4-hexadiene, 1 ,3-octadiene, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,4-diphenyl-1,3-butadiene, 1-methoxy-1,3 -butadiene, 2-methoxy-1,3-butadiene, 1-ethoxy-1,3-butadiene, 2-ethoxy-1,3-butadiene, 2-nitro yl-1,3-butadiene, chloroprene, 1-chloro-1,3-butadiene, 1-bromo-1,3-butadiene, tropone, basil terpene (ocimene), ferrandrene, myrcene (myrcene), farnesene (farnesene), sorbic acid, sorbic acid ester, sorbate and other sorbic acids, abietic acid, etc. Conjugated dienes composed of conjugated structures; 2,4,6-octatriene-1-carboxylic acid, eleostearic acid, tung oil, cholecalciferol, etc. are composed of conjugated structures of 3 carbon-carbon double bonds The conjugated triene can also be used in combination of two or more kinds of the conjugated polyene. Preferred conjugated polyenes are sorbic acids such as sorbic acid, sorbic acid ester, and sorbic acid salt.

As the lubricating agent used in the present invention, higher fatty acids, for example, higher fatty acids such as oleic acid, lauric acid, palmitic acid, myristic acid, stearic acid, behenic acid, etc.; aluminum salts of these higher fatty acids, Metal salts of higher fatty acids such as calcium salts, zinc salts, magnesium salts, barium salts; esters of higher fatty acids such as methyl esters, isopropyl esters, butyl esters, and octyl esters of the above-mentioned higher fatty acids; amide stearate, behenic acid Saturated higher fatty acid amide such as amide, unsaturated higher fatty acid amide such as oleic acid amide, erucic acid amide, vinyl bis-stearyl amide, vinyl bis-oleic acid amide, vinyl bis-erucic acid amide, The amides of higher fatty acids such as bis-higher fatty acid amides such as vinylbislaurate amides can be used alone or in combination of two or more.

The EVOH resin composition is advantageous for more efficient preparation of EVOH films formed therefrom. Appropriate methods and equipment for preparing EVOH membranes may include methods and equipment readily understood by those of ordinary skill in the art. The inventor believes that by controlling the surface roughness of the EVOH resin composition, the EVOH resin composition can reduce the torsion force in the extruder, and can also reduce the gel generation of the film or multi-layer structure formed by the EVOH resin composition, The appearance of the film or multilayer structure formed by the EVOH resin composition is improved.

The EVOH resin composition of the present invention usually has a moisture content in a specific range. For example, taking volatile content as the evaluation of the moisture content of the EVOH resin composition, the moisture content of the EVOH resin composition can be less than or equal to 1 weight percent (wt%), less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1%, or between 0.01 and 1 wt%, between 0.08 and 1 wt%, or Between 0.05 and 1 wt%. It was unexpectedly found that the moisture content of the EVOH resin composition must be controlled within a certain range. When the moisture content is too high, the film or multi-layer structure formed by the EVOH resin composition will cause bubbles, uneven film thickness and increase in flow marks, etc. There are problems in subsequent processing. Volatile matter, analyzed using ISO 14663-2 Annex A method.

In yet another aspect, the present invention provides a multilayer structure having at least one layer formed of the EVOH resin composition of the present invention; at least one polymer layer; and at least one adhesive layer. The polymer layer system may be selected from low density polyethylene layers, polyethylene grafted maleic anhydride layers, polypropylene layers, nylon layers, and combinations thereof. The adhesive layer may be a tie layer, such as ARKEMA OREVAC 18729 from ARKEMA Corporation.

The EVOH resin composition is advantageous for more efficient preparation of EVOH films formed therefrom. Appropriate methods and equipment for preparing EVOH membranes may include methods and equipment readily understood by those of ordinary skill in the art. Example

The following non-limiting examples of aspects of the invention are provided primarily to illustrate the aspects of the invention and the benefits achieved. Example 1

A non-limiting method of preparing EVOH particles formed from EVOH resin compositions is provided below. Six non-limiting Example EVOH resin compositions (Examples EVOH 1-6) and four Comparative Example EVOH resin compositions (Comparative Examples EVOH 1-4) were prepared according to methods similar to those disclosed below. However, the specific methods for preparing Examples EVOH 1-6 and Comparative Examples EVOH 1-4 generally differ from the methods disclosed below in one or more respects. Example EVOH 1 Granules

Add 500 kg of vinyl acetate, 100 kg of methanol, 0.0585 kg of acetyl peroxide, and 0.015 kg of citric acid to a polymerization kettle equipped with a cooling coil. After the polymerization kettle was temporarily replaced with nitrogen, it was replaced with ethylene and pressed until the pressure of ethylene. becomes 45kg/cm ² . Under ethylene pressure, the temperature was raised to 67°C with stirring 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. Thus, an ethylene-vinyl acetate copolymer having an ethylene structural unit content of 44 mole % was obtained. Then, the reaction solution containing the ethylene-vinyl acetate copolymer was supplied to a distillation column, and methanol vapor was introduced from the lower part of the column to remove unreacted vinyl acetate, thereby obtaining a methanol solution of the ethylene-vinyl acetate copolymer.

A component formed by polymerizing ethylene monomer and vinyl acetate monomer (ethylene-vinyl acetate copolymer, hereinafter referred to as "EVAC" polymer) is saponified with a degree of saponification of 99.5% to prepare EVOH polymer. Subsequently, EVOH was dissolved in a solution containing methanol and water (ratio 60:40). The EVOH/methanol/water solution was placed at 60°C for 1 hour to facilitate the dissolution of EVOH in the EVOH/methanol/water solution. The EVOH/methanol/water solution had a solids content of 41 wt.%.

Then, the solution of methanol, water and EVOH was pelletized by underwater pelletization. Specifically, the aforementioned solution of methanol, water, and EVOH was pumped into the feed pipe at a flow rate of 120 L/min using a pump, then fed into an input pipe with a diameter of 2.8 mm, and cut at 1500 rpm using a rotary knife to obtain Granules of EVOH. At the same time, circulating condensed water at 5°C was used to cool the EVOH pellets. Subsequently, the EVOH particles were centrifuged to separate out the EVOH particles. The separated EVOH particles were washed with water, and the EVOH particles were immersed in a boric acid/sodium acetate solution, then dried and calcium stearate was added to obtain EVOH pellets with a long side of 3.0 mm and a short side of 2.4 mm , and finally the pellets are transported and bagged.

The so-called conveying and bagging is carried out under the following conditions: the moisture content of EVOH particles is 0.01%, the conveying form is air conveying, the diameter of the pipeline is 3 inches, the number of elbows is 2, the length of the pipeline is 20 meters, and the conveying speed is 40 m/min , the moisture content of EVOH pellets after bagging is also 0.01%. Example EVOH 2 Granules

The EVOH pellets for Example EVOH 2 were prepared using a similar procedure to Example EVOH 1 pellets. However, the EVOH particle size of Example EVOH 2 is a round granular particle with a long side of 1.5 mm and a short side of 1.5 mm, and the conveying bagging system is carried out in the following cases: the moisture content of Example EVOH 2 is 0.2%, and the conveying form The same is used for air transportation. The diameter of the pipeline is 2.5 inches, the number of elbows is 4, the length of the pipeline is 15 meters, the conveying speed is 20 m/min, and the moisture content of EVOH pellets after bagging is also 0.2%. Example EVOH 3 Granules

EVOH granules for Example EVOH 3 were prepared using a similar procedure to Example EVOH 1 granules. However, the EVOH particle size of Example EVOH 3 was round granular particles with a long side of 5.0 mm and a short side of 5.0 mm, and the conveying bagging system was carried out under the following conditions: the moisture content of Example EVOH 3 was 0.3%, and the belt Conveying method, the pipeline diameter is 6 inches, the belt roughness (Rz) is 15μm, the number of elbows is 3, the pipeline length is 10 meters, the conveying speed is 30m/min, and the moisture content of EVOH pellets after bagging is also 0.3%. Example EVOH 4 Granules

EVOH granules for Example EVOH 4 were prepared using a similar procedure to Example EVOH 1 granules. However, when preparing the EVOH granules of Example EVOH 4, the conveying and bagging were carried out under the following conditions: The ethylene content of Example EVOH 4 was 28 mol ratio, and the moisture content was 0.08%. It is 6 inches, the belt roughness (Rz) is 21 μm, the number of elbows is 0, the pipeline length is 20 meters, the conveying speed is 10 m/min, and the moisture content of EVOH pellets after bagging is also 0.08%. Example EVOH 5 Granules

EVOH granules for Example EVOH 5 were prepared using a similar procedure to Example EVOH 1 granules. However, in the preparation of EVOH granules of Example EVOH 5, the conveying and bagging was carried out in the following conditions: Example EVOH 5 had an ethylene content of 28 molar ratio and a moisture content of 0.7%, and was also transported by belt conveying, and the diameter of the pipeline was It is 5 inches, the belt roughness (Rz) is 18μm, the number of elbows is 2, the pipeline length is 20 meters, the conveying speed is 7m/min, and the moisture content of EVOH pellets after bagging is also 0.7%. Example EVOH 6 Granules

Using a similar procedure to Example EVOH 1 granules, EVOH granules for Example EVOH 6 were prepared. However, when preparing the EVOH pellets of Example EVOH 6, the delivery bagging was carried out as follows: Example EVOH 6 had a moisture content of 1%, the delivery form was air delivery, the line diameter was 3 inches, and the number of elbows was 3 , the pipeline length is 20 meters, the conveying speed is 30m/min, and the moisture content of EVOH pellets after bagging is also 1%. Comparative Example EVOH 1 Granule

EVOH granules for Comparative Example EVOH 1 were prepared using a similar procedure to Example EVOH 1 granules. However, when preparing EVOH pellets of Comparative Example EVOH 1, the conveying and bagging was carried out under the following conditions: Comparative Example EVOH 1 had a moisture content of 0.8%, was transported by air, the diameter of the pipeline was 2 inches, and the number of elbows was 6. The length of the pipeline is 30 meters, the conveying speed is 80m/min, and the moisture content of EVOH pellets after bagging is also 0.8%. Comparative Example EVOH 2 Granules

EVOH granules for Comparative Example EVOH 2 were prepared using a similar procedure to Example EVOH 1 granules. However, when preparing EVOH pellets of Comparative Example EVOH 2, the conveying and bagging were carried out under the following conditions: Comparative Example EVOH 2 had a moisture content of 0.7% and was conveyed by belt conveying with a line diameter of 1 inch and a belt roughness ( Rz) is 44 μm, the number of elbows is 8, the pipeline length is 20 meters, the conveying speed is 10 m/min, and the moisture content of EVOH pellets after bagging is also 0.7%. Comparative Example EVOH 3 Granules

EVOH granules for Comparative Example EVOH 3 were prepared using a similar procedure to Example EVOH 1 granules. However, when preparing the EVOH pellets of Comparative Example EVOH 3, the conveying and bagging were carried out under the following conditions: The moisture content of Comparative Example EVOH 3 was 0.05%, and was also conveyed by belt conveying, the diameter of the pipeline was 8 inches, and the belt roughness was (Rz) is 5 μm, the pipeline length is 5 meters, the conveying speed is 5 m/min, and the moisture content of EVOH pellets after bagging is also 0.05%. Comparative Example EVOH 4 Granules

EVOH pellets for Comparative Example EVOH 4 were prepared using a similar procedure to Example EVOH 1 pellets. However, when preparing EVOH pellets of Comparative Example EVOH 4, the conveying and bagging were carried out under the following conditions: The moisture content of Comparative Example EVOH 4 was 0.4%, and was also conveyed by belt conveying, the diameter of the pipeline was 2 inches, and the roughness of the belt was (Rz) is 20 μm, the number of elbows is 5, the pipeline length is 20 meters, the conveying speed is 50 m/min, and the moisture content of EVOH pellets after bagging is also 0.4%. Example 2

Films were formed using the particles of Example EVOH 1-6, respectively, according to the method described below. Example EVOH 1-6 pellets and Comparative Example EVOH 1-4 pellets were fed into a single-layer T-die cast film extruder (optical control system MEV4) to prepare films. The thickness of the films formed from Example EVOH 1-6 particles and Comparative Example EVOH 1-4 particles were each 20 μm. The temperature of the extruder was set to 220°C, and the temperature of the die (ie, the T-die) was set to 230°C. The rotation frequency of the screw was 7 rpm (rotations/minutes). Example 3

Example EVOH 1-6 particles and Comparative Example EVOH 1-4 particles were evaluated to determine the properties of these EVOH particles and the films formed therefrom. As described above, Example EVOH 1-6 particles were prepared according to a method similar to that described in Example 1 above. However, the method of preparing EVOH 1-6 particles differed for EVOH particles prepared with different Sdq, Sdr, Sa, Sv, Rz, boron content or alkali metal content. Comparative Example EVOH 1-4 particles were also prepared according to a method similar to that described in Example 1 .

The average torque and extruder current of the single-screw extruder were further evaluated. Films were formed from Examples EVOH 1-6 and Comparative Examples EVOH 1-4 individually, in a manner similar to that described in Example 2, and the films were evaluated to determine the size and amount of gel (Gel) on the films. The Gel refers to gels or protrusions induced by thickening or colloidization produced when EVOH is made into a thin film.

Table 1 below provides a summary of some properties of Example EVOH Particles 1-6 and Comparative Examples EVOH Particles 1-4, namely Sdq, Sdr, Sa, Sv, Rz, boron content, alkali metal content, extruder average torque and pressure The outgoing current, and the amount of Gel of the films formed from Example EVOH 1-6 and Comparative Example EVOH particles 1-4 yield the situation.

Table 1 Example EVOH 1 Example EVOH 2 Example EVOH 3 Example EVOH 4 Example EVOH 5 Example EVOH 6 Technical characteristics Sdq rms slope 0.001 0.1 1.1 3.3 9.23 8.15 Sdr interface expansion area ratio (%) 0.1 2.2 11.3 50.2 99.2 96.3 Arithmetic mean height of Sa surface (μm) 0.005 0.03 0.08 0.32 0.94 0.91 Sv surface maximum valley depth (μm) 0.01 0.45 1.1 3.1 5 4.8 Rz line maximum height (μm) 0.021 0.899 9.34 0.644 5.41 13.24 Boron content (ppm) 130 210 10 490 380 240 Sodium content (ppm) 240 170 10 210 320 130 effect 0~100μm Gel O O O O O △ 100~200 μm Gel O O O △ O O ＞200μm Gel O O O O O O Average torque of single screw extruder (Torque) twenty one 44 31 52 38 65 Single screw extruder current (Å) 34 52 46 67 44 77

Table 1 (continued) Comparative Example EVOH 1 Comparative Example EVOH 2 Comparative Example EVOH 3 Comparative Example EVOH 4 Technical characteristics Sdq rms slope 19 33.2 0.0003 18.35 Sdr interface expansion area ratio (%) 135.6 221.4 0.001 112.7 Arithmetic mean height of Sa surface (μm) 6.3 7.7 0.001 2.34 Sv surface maximum valley depth (μm) 15 20 0.004 12 Rz line maximum height (μm) 11.05 29.73 0.01 3.66 Boron content (ppm) 310 250 130 50 Sodium content (ppm) 110 200 40 140 effect 0~100μm Gel O O X O 100~200μm Gel X X O X ＞200μm Gel X X O O Average torque of single screw extruder (Torque) 179 192 10 83.2 Single screw extruder current (Å) 317 412 11 95.3

The boron content of each Example and Comparative Example was measured by the following method. First, a 0.1 g EVOH particle sample was decomposed using concentrated nitric acid and microwave to make the EVOH particles form a sample solution. The sample solution was then diluted with pure water to adjust its concentration to 0.75 mg/ml. Use an inductively coupled plasma emission spectrochemical analyzer (ICP emission spectrochemical analysis device, ICP-OES; analyzer: iCAP7000 (Thermo Fisher Scientific, Thermo) to measure the boron content in the sample solution. The boron content refers to Corresponds to the measurement of the boron content derived from the boron compound used.

In addition, the alkali metal content in the EVOH pellets of the respective Examples and Comparative Examples was also measured. Take 2 g of the above EVOH particles into a platinum dish, add several mL of sulfuric acid, and heat with a gas burner. After confirming that the pellets are carbonized and the sulfuric acid white smoke disappears, add a few drops of sulfuric acid and reheat. Repeat this until the organic matter is gone, making it completely ashed. The container after the ashing was left to cool, and 1 mL of hydrochloric acid was added to dissolve it. The hydrochloric acid solution was washed with ultrapure water, and the volume was adjusted to 50 mL. The alkali metal content in this sample solution was measured with an inductively coupled plasma spectrometer (ICP-AES) (manufactured by Agilent Technology, model 720-ES). Finally, the alkali metal content in the pellets of the EVOH composition described above was converted from the alkali metal concentration in the solution.

In order to evaluate the particle surface roughness of Examples EVOH 1-6 and Comparative Examples EVOH 1-4, the EVOH particles were placed flat on the plate to measure the surface roughness of the particles, and the data when the inclination was greater than 0.5 were excluded from the measurement to ensure that The scanning plane is relatively horizontal (inclination=maximum height Sz of plane/side length of analysis range 129 μm). The laser microscope was a LEXT OLS5000-SAF manufactured by Olympus, and the images were made at an air temperature of 24±3°C and a relative humidity of 63±3%. The filter is set to no filter. The light source is a 405 nm-wavelength light source. The objective lens is 100x magnification (MPLAPON-100xLEXT). Optical zoom was set to 1.0x. The image area is set to 129 µm x 129 µm (when measuring Rz, take the center line of the image area). Resolution is set to 1024px x 1024px. Measure the value of 100 particles and take the average value. Among them, Sdq, Sdr, Sa and Sv are measured by ISO 25178:2012 method; Rz is measured by JIS B 0601 (2001) method.

For example EVOH 1-6 and comparative example EVOH 1-4, the extruder torque calculation and current calculation were performed during processing, and the EVOH particles were extruded by a single-screw extruder (model ME25/5800V4, brand OCS), measured The torque value and current value of the extruder, and the extrusion conditions are as follows: the screw temperature is Zone1 195℃, Zone2 215℃, Zone3 220℃, Zone4 230℃, Zone5 230℃; the screw speed is 7 rpm. The calculation time is 10 to 60 minutes, 1 point is recorded every 1 minute, and the average value is calculated.

After the example EVOH 1-6 and the comparative example EVOH 1-4 were processed into single-layer films, the Gel quantity of the single-layer films was analyzed by the FSA-100 film quality test system, and evaluated according to the evaluation standard. The size of Gel formed is divided into three categories. The first category is Gel <100 μm. If the number is less than 450, "O" is the best; if the number is 450~1000, "Δ" is acceptable. ; If the number is greater than 1000, it will be represented by "X". The second category is Gel between 100 and 200 μm. If the number is less than 50, "O" is the best; if the number is 50-100, it is acceptable with "Δ"; if the number is greater than 100, then Bad with an "X". The third category is Gel > 200 μm. If the number is less than 10, "O" is the best; if the number is 10~20, it is acceptable with "Δ"; if the number is greater than 20, "X" " means bad.

The results show that Examples EVOH 1-6 have lower torque output (21 to 52 Torque), current (34 to 67 Å) and less Gel generation, and the films formed by Example EVOH 1-6 have a condensation of <100 μm. The number of gels was less than 450, the number of gels from 100 to 200 μm was less than 100, and the number of gels >200 μm was less than 10. Examples EVOH 1-6 are shown to exhibit excellent processing torque output and film properties.

The inventors found that when the surface roughness of EVOH particles is too high, when the particles are rubbed during single-screw processing, local overheating is likely to cause crosslinking, and large gels are likely to be generated during processing. When the surface roughness of EVOH particles is too low, the frictional heat of EVOH during processing is insufficient and cannot be melted, and tiny gels will be formed after extrusion. Therefore, the surface roughness of EVOH particles needs to be controlled within a certain range to avoid gel formation.

By comparing the examples and comparative examples in Table 1, the number of elbows in Comparative Example EVOH 1 is too large, the length of the pipeline is too high, and the conveying speed is too fast, causing particles to collide and rub against each other, making the surface roughness high; Comparative Example EVOH 2 The size of the pipeline is too small, the roughness of the belt is too high, and the number of elbows is too large, causing particles to collide and rub against each other, which makes the surface roughness high; the pipeline size of the comparative example EVOH 3 is too large, the roughness of the belt is low, the length of the pipeline is low, The conveying speed is low, resulting in insufficient surface roughness.

The inventor found that the variable factors of regulating the conveying procedure during EVOH particle processing can obtain the desired surface roughness of the present invention, which has the following characteristics: too small pipeline size, too high belt roughness, too many elbows, too long pipeline length, and conveying speed. Too fast, etc., will cause collision and friction of particles/particles during transportation, which will increase the roughness of EVOH particles.

According to the results tested by the present invention, as long as the EVOH surface roughness is controlled within a specific range, the torque current in the single-screw extruder and the gel generation of the EVOH film can be reduced. As shown in Table 1, Comparative Examples EVOH 1, 2, and 4 had Sdq, Sdr, Sa, and Sv beyond the expected ranges described herein, and the test results all had higher extruder torque output and extruder current, and The films formed therefrom produce excessive gelation. Comparative Example EVOH 3 has Sdq, Sdr, Sa, and Sv below the desired ranges described herein, and the test results have good torque output and current, but the film formed from Comparative Example EVOH 3 produced too much gel, and has undesired properties.

To sum up, the EVOH resin composition of the present invention has low surface roughness, especially the surface roughness is between 0.0005 and 13 Sdq. The control of the surface roughness of the EVOH resin composition can be achieved by manipulating the variables in the delivery stage of the EVOH process. The EVOH resin composition can be used to make films or multilayer structures. The inventors found that by controlling the surface roughness of EVOH particles, the torque output during processing can be reduced, and the friction between particles or between the particles and the screw can be reduced, which not only makes the appearance of the film highly uniform, but also reduces energy consumption.

All ranges provided herein are intended to include each specific range within the given range and combinations of subranges between the given ranges. Furthermore, all ranges provided herein are inclusive of the endpoints of the stated range unless otherwise indicated. Thus, the range 1-5 specifically includes 1, 2, 3, 4, and 5, as well as subranges such as 2-5, 3-5, 2-3, 2-4, 1-4, and the like.

All publications and patent applications cited in this specification are incorporated herein by reference, and each individual publication or patent application is expressly and individually indicated to be incorporated by reference for any and all purposes. In the event of inconsistency between this document and any publication or patent application incorporated herein by reference, this document controls.

The terms "including", "having" and "comprising" as used herein have an open, non-limiting meaning. The terms "a" and "the" should be understood to encompass both the plural and the singular. The term "one or more" means "at least one" and thus may include a single feature or a mixture/combination of features.

Except in the working examples or where otherwise indicated, all numbers indicating amounts of ingredients and/or reaction conditions may in all cases be modified using the term "about", meaning within ±5% of the indicated number . As used herein, the terms "substantially free" or "substantially free" refer to less than about 2% of a particular characteristic. All elements or features expressly stated herein may be negatively excluded from the scope of the claim.

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Claims (15)

An ethylene-vinyl alcohol copolymer resin composition, which is in the form of particles, comprising an ethylene-vinyl alcohol copolymer resin; wherein the ethylene-vinyl alcohol copolymer resin composition has a surface, and the surface has between 0.0005 to 0.0005 The root mean square slope (Sdq) of 13 and its maximum outer diameter or major axis is 1.5 to 5.0 mm. The ethylene-vinyl alcohol copolymer resin composition as described in claim 1 of the claimed scope, the surface of the ethylene-vinyl alcohol copolymer resin composition has an interfacial development ratio (Sdr) ranging from 0.05 to 110%. According to the ethylene-vinyl alcohol copolymer resin composition described in claim 1, the surface of the ethylene-vinyl alcohol copolymer resin composition has a surface arithmetic mean height (Sa) ranging from 0.003 to 1.5 μm. According to the ethylene-vinyl alcohol copolymer resin composition described in claim 1, the surface of the ethylene-vinyl alcohol copolymer resin composition has a maximum surface valley depth (Sv) ranging from 0.005 to 8 μm. According to the ethylene-vinyl alcohol copolymer resin composition described in item 1 of the claimed scope, the ethylene content of the ethylene-vinyl alcohol copolymer resin ranges from 20 to 48 mole percent. According to the ethylene-vinyl alcohol copolymer resin composition described in item 1 of the claimed scope, the saponification degree of the ethylene-vinyl alcohol copolymer resin is greater than 99.5 mole percent. According to the ethylene-vinyl alcohol copolymer resin composition described in any one of claims 1 to 6, the maximum height (Rz) of the line on the surface is between 0.02 and 15 μm. According to the ethylene-vinyl alcohol copolymer resin composition described in any one of claims 1 to 6, the maximum height (Rz) of the line on the surface is between 0.02 and 9.9 μm. The ethylene-vinyl alcohol copolymer resin composition described in item 1 of the scope of the application has a water content of less than or equal to 1 weight percent. The ethylene-vinyl alcohol copolymer resin composition as described in item 1 of the claimed scope has a boron content of 5-550 ppm. The ethylene-vinyl alcohol copolymer resin composition as described in item 1 of the claimed scope has an alkali metal content of 5-550 ppm. The ethylene-vinyl alcohol copolymer resin composition according to any one of claims 1 to 6, further comprising one of the group consisting of cinnamic acid, conjugated polyene, slip agent and alkaline earth metal, or its combination. An ethylene-vinyl alcohol copolymer film, which is formed from the ethylene-vinyl alcohol copolymer resin composition described in any one of the patent application scopes 1 to 12. A multilayer structure comprising: (a) at least one layer formed from the ethylene-vinyl alcohol copolymer resin of any one of claims 1 to 12; (b) at least one polymer layer; and (c) at least one adhesive layer . The multilayer structure of claim 14, wherein 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 group, and the adhesive layer is a tie layer.