Water-blocking and oxygen-blocking polyethylene composite material and preparation method thereof

Abstract

The invention provides a water-blocking and oxygen-blocking polyethylene composite material and a preparation method thereof. The water-blocking and oxygen-blocking polyethylene composite material is prepared from the following components in parts by weight: 80-95 parts of polyethylene, 5-20 parts of ethylene-vinyl alcohol copolymer, 2-10 parts of hydroxylated glass fiber, 2-8 parts of montmorillonite, 0.5-4 parts of polyhydroxy sulfonic acid quaternary ammonium salt and 0.1-3 parts of auxiliaries. The composite material provided by the invention has high oxygen resistance and water resistance, the tensile property and the impact strength also meet the use requirements, and the composite material is suitable for preparing a polyethylene film.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic packaging, and in particular relates to a water-blocking and oxygen-blocking polyethylene composite material and a preparation method thereof. Background Art

[0002] Polyethylene is one of the commonly used packaging materials. It has the advantages of low price, easy processing, stable chemical properties, etc. It is widely used in food and medical packaging. Barrier property is a basic requirement for packaging materials. It can prevent the invasion of external substances such as oxygen, water vapor, bacteria, etc., and extend the shelf life of the substances in the package. Since polyethylene has low polarity, according to the principle of like dissolves like, its water permeability is low, but its air permeability is high, that is, its oxygen barrier property is poor.

[0003] Ethylene-vinyl alcohol copolymer (EVOH) combines the good processability of polyethylene with the high gas barrier properties of polyvinyl alcohol. There are hydroxyl groups on the EVOH molecular chain, and the large number of hydrogen bonds weaken the movement of the molecular chain and increase the density of the material, so it has excellent gas barrier properties. However, the polar polymer structure of EVOH makes it hydrophilic and hygroscopic, and its gas barrier properties will decrease with the increase of humidity. Under high humidity conditions, the barrier properties will drop sharply.

[0004] Blending polyethylene with EVOH can complement each other and reduce costs, but non-polar polyolefins and highly polar barrier materials EVOH have poor compatibility, and material blending will destroy the continuity of high barrier materials and affect barrier properties. In addition, problems such as low mechanical strength of polyethylene also need to be solved in the blending modification process. Therefore, it is necessary to provide a polyethylene composite material with good water and oxygen barrier properties and mechanical properties that meet the use requirements to solve the problems existing in the prior art. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a water- and oxygen-barrier polyethylene composite material. The polyethylene composite material of the present invention has high oxygen barrier and water barrier properties, and its tensile properties and impact strength meet the use requirements, and is suitable for preparing packaging materials such as polyethylene films.

[0006] Another object of the present invention is to provide a method for preparing the water- and oxygen-barrier polyethylene composite material.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A water-blocking and oxygen-blocking polyethylene composite material, the water-blocking and oxygen-blocking polyethylene composite material comprises the following raw material components calculated by weight:

[0009]

[0010] Preferably, the polyethylene is at least one of low-density polyethylene or high-density polyethylene.

[0011] Further preferably, the polyethylene is a mixture of low-density polyethylene and high-density polyethylene, and the mass ratio of the low-density polyethylene to the high-density polyethylene is (60-65):(20-30).

[0012] Preferably, the hydroxylated glass fiber is obtained by heating glass fiber in a strong acid.

[0013] Further preferably, the hydroxylated glass fiber is obtained by heating the glass fiber in a hydrochloric acid solution with a concentration of 8 to 20% at 90 to 100° C. for 6 to 12 hours, followed by washing and drying.

[0014] Preferably, the general structural formula of the polyhydroxysulfonic acid quaternary ammonium salt is as shown in formula (I):

[0015]

[0016] Among them, the n of the alkyl chain on the quaternary ammonium cation 1 、n 2 、n 3 and n 4 The values ​​are independently selected from 1 to 18 and are not 1 at the same time; the anion containing R in formula (I) is

[0017] Preferably, the preparation method of the polyhydroxysulfonic acid quaternary ammonium salt comprises the following steps:

[0018] S1, dissolving a halide salt of a quaternary ammonium compound in a solvent, exchanging the halide anion for a hydroxide anion through a hydroxide exchange column to form a hydroxide containing a quaternary ammonium cation;

[0019] S2, adding polyhydroxy sulfonic acid in an equimolar amount to the hydroxide containing quaternary ammonium cations, stirring for neutralization reaction, and vacuum baking to remove the solvent to obtain the polyhydroxy sulfonic acid quaternary ammonium salt.

[0020] Preferably, the solvent in step S1 is a combination of one or more of water, methanol, ethanol, propanol, butanol and isopropanol.

[0021] Preferably, the quaternary ammonium cation is a mixture of one or more of dodecyltrimethylammonium ion, tetradecyltrimethylammonium ion, hexadecyltrimethylammonium ion, octadecyltrimethylammonium ion, dioctyldimethylammonium ion, didecyldimethylammonium ion, didodecyldimethylammonium ion, ditetradecyldimethylammonium ion, dihexadecyldimethylammonium ion and dioctadecyldimethylammonium ion.

[0022] Preferably, the polyhydroxy sulfonic acid is a mixture of one or more of 1,2-dihydroxyethanesulfonic acid, 2-(diethanolamino)ethanesulfonic acid, and 3-[2-(4-hydroxybutoxy)-1-[(2-hydroxyethoxy)methyl]ethoxy]-1-propanesulfonic acid.

[0023] Preferably, the auxiliary agent includes a mixture of one or more of an antioxidant, an antistatic agent, a compatibilizer, and a toughening agent.

[0024] Preferably, the preparation method of the water-blocking and oxygen-blocking polyethylene composite material comprises the following steps:

[0025] S01, adding montmorillonite to deionized water, heating and stirring until the montmorillonite is fully dissolved, adding quaternary ammonium salt of polyhydroxysulfonic acid and continuing heating to react;

[0026] S02, add hydroxylated glass fiber, and stir to react at room temperature;

[0027] S03, the product of step S02 is centrifuged, washed, and dried to obtain an organic montmorillonite-glass fiber composite;

[0028] S04, blending polyethylene, ethylene-vinyl alcohol copolymer, the organic montmorillonite-glass fiber composite and the additives in step S03, heating and melting, and extruding and granulating to obtain the water-blocking and oxygen-blocking polyethylene composite material.

[0029] Further preferably, the heating temperature in step S01 is 50-60°C, the room temperature in step S02 is 10-40°C, and the heating temperature in step S04 is 180-230°C.

[0030] Further preferably, the heating reaction time in step S01 is 2 to 4 hours, and the stirring reaction time in step S02 is 2 to 4 hours.

[0031] Montmorillonite is a nano-sized silicate sheet with a negatively charged surface and a layered structure. When used as a polymer filler, it can extend the permeation path of water or small gas molecules in the material, which helps to improve the barrier properties of the material. However, the presence of a large number of inorganic ions between nano-montmorillonite layers makes it hydrophilic and oleophobic, and it has poor compatibility with non-polar polymers such as polyethylene, which is not conducive to its dispersion in polyethylene, so that the barrier properties of polyethylene materials are not significantly improved; on the other hand, for packaging materials with a smaller thickness such as polyethylene film, in order to obtain high barrier properties, more montmorillonite needs to be added, but when the amount of montmorillonite is too much, the nanoparticles are prone to agglomeration in the composite material, which in turn will lead to a significant deterioration of the gas barrier properties and mechanical properties of the polymer. The orientation degree of two-dimensional nanomaterials in the matrix material is closely related to the improvement of their gas barrier properties. Therefore, it is very important to ensure their full distribution and arrangement, and to reduce the amount while improving the barrier properties.

[0032] The present invention adopts polyhydroxy sulfonic acid quaternary ammonium salt to carry out organic modification on montmorillonite, introduces oleophilic alkane chain segments on the surface of montmorillonite sheet by replacing quaternary ammonium cations with cations between montmorillonite layers; and the Si-O structure on the surface of glass fiber is fully exposed to generate hydroxyl groups through acid erosion treatment, and hydrogen bonds are generated with the hydroxyl groups of polyhydroxy sulfonic acid quaternary ammonium salt to form a composite material in which organic modified montmorillonite is coated on the surface of glass fiber. Glass fiber has high strength and high modulus, and can improve the mechanical properties and thermal stability of the material by adding it to polyethylene. In the process of processing and forming, the glass fiber is arranged in parallel along the stress (flow) direction, and the montmorillonite forms hydrogen bonds with the hydroxylated glass fiber due to the polyhydroxy sulfonic acid quaternary ammonium salt, and then is arranged and distributed in a nano-sheet form along the direction of the glass fiber surface to form a barrier layer, which is conducive to further improving the barrier effect.

[0033] The present invention melt-blends polyethylene, EVOH and an organic modified montmorillonite-glass fiber composite. Hydrogen bonding occurs between hydroxyl groups of EVOH and hydroxyl groups on the organic modified montmorillonite-glass fiber composite. On the one hand, the density of the material is increased, and the water and oxygen barrier properties are improved. On the other hand, the alkane chain segments of the quaternary ammonium cations in the organic modified montmorillonite-glass fiber composite are compatible with the polyethylene chain segments, so that the organic modified montmorillonite-glass fiber composite and EVOH form a stable dispersed phase in a polyethylene matrix.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention mixes polyhydroxy sulfonic acid quaternary ammonium salt, montmorillonite and hydroxylated glass fiber for reaction, wherein the quaternary ammonium cation of the polyhydroxy sulfonic acid quaternary ammonium salt has an oleophilic alkane chain segment, which is introduced into the surface of the montmorillonite through cation replacement to improve its hydrophobicity and compatibility with polyethylene, and the hydroxyl groups of the polyhydroxy sulfonic acid quaternary ammonium salt form hydrogen bonds with the hydroxyl groups of the glass fiber to generate a composite material in which the organic modified montmorillonite is coated on the surface of the glass fiber. During the processing and molding process, the glass fiber is arranged in parallel along the stress direction, and the montmorillonite is arranged and distributed in a direction along the surface of the glass fiber in the form of nanosheets. The impermeability of the montmorillonite and the glass fiber and the bending of the permeation path induced by the presence of the nanomaterial reduce the gas and water permeability, and the orderly arrangement and distribution of the nanosheet layer further improves the barrier effect.

[0036] (2) The present invention uses ethylene-vinyl alcohol copolymer and organic modified montmorillonite-glass fiber composite to blend and modify polyethylene. The hydroxyl groups of EVOH and the hydroxyl groups on the organic modified montmorillonite-glass fiber composite have hydrogen bonding forces, which increases the density of the material and improves the barrier properties. The good compatibility of the alkane chain segments of the quaternary ammonium cations in the organic modified montmorillonite-glass fiber composite with the polyethylene segments also improves the dispersion stability of the montmorillonite-glass fiber composite and EVOH in the polyethylene matrix. The two work synergistically to jointly improve the water and oxygen barrier properties and mechanical strength of polyethylene. DETAILED DESCRIPTION

[0037] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0038] The following raw materials were used in the examples and comparative examples of the present invention:

[0039] Low-density polyethylene (LDPE): MG70 from Qatar Petrochemical;

[0040] High-density polyethylene (HDPE): HD5502FT from Shanghai Secco;

[0041] Ethylene vinyl alcohol copolymer (EVOH): F104B from Kuraray of Japan;

[0042] PE-MAH compatibilizer: 41E710 from DuPont, USA;

[0043] Montmorillonite: K-10 from Shanghai Dibai;

[0044] Glass fiber: Wuhe County Weijia Composite Materials Co., Ltd.

[0045] (I) Test method

[0046] According to GB / T 1038-2022, oxygen permeability is tested at 0% RH and 80% RH at 23°C. According to GB / T 1037-2021, water vapor permeability is tested at 38°C and 90% RH. According to GB / T 1040.1-2006, tensile strength and elongation at break are tested at a tensile speed of 50 mm / min. According to GB / T1843-2008, impact strength is tested.

[0047] (II) Preparation method

[0048] (1) Preparation of hydroxylated glass fibers

[0049] The glass fiber is immersed in a hydrochloric acid solution with a concentration of 10%, heated at 100° C. for reaction for 8 hours, washed and dried to obtain the hydroxylated glass fiber.

[0050] (2) Preparation of quaternary ammonium salt of polyhydroxysulfonic acid

[0051] ① Preparation of 1# polyhydroxysulfonic acid quaternary ammonium salt

[0052] S1, dissolving 3.92g (0.01mol) of octadecyltrimethylammonium bromide in 100ml of ethanol, exchanging the bromide anion with the hydroxide anion through a hydroxide exchange column to form a hydroxide solution of octadecyltrimethylammonium ions;

[0053] S2, 1.41g (0.01mol) 1,2-dihydroxyethanesulfonic acid (CAS No.: 115465-05-9, ) is added to the hydroxide solution of octadecyltrimethylammonium ion, stirred for reaction for 10 to 15 minutes, and vacuum baked to remove the solvent to obtain 1# polyhydroxysulfonic acid quaternary ammonium salt.

[0054] ② Preparation of 2# polyhydroxysulfonic acid quaternary ammonium salt

[0055] S1, dissolving 4.62g (0.01mol) of didodecyldimethylammonium bromide in 100ml of isopropanol, exchanging the bromide anion with the hydroxide anion through a hydroxide exchange column to form a hydroxide solution of didodecyldimethylammonium ions;

[0056] S2, 2.13g (0.01mol) 2-(diethanolamino)ethanesulfonic acid (CAS No.: 10191-18-1, ) is added to the hydroxide solution of didodecyldimethylammonium ion, stirred for reaction for 10 to 15 minutes, and vacuum baked to remove the solvent to obtain 2# polyhydroxysulfonic acid quaternary ammonium salt.

[0057] ③ Preparation of 3# polyhydroxysulfonic acid quaternary ammonium salt

[0058] S1, dissolving 5.75g (0.01mol) of dihexadecyldimethylammonium bromide in 120ml of isopropanol, exchanging the bromide anion with the hydroxide anion through a hydroxide exchange column to form a hydroxide solution of dihexadecyldimethylammonium ions;

[0059] S2, 3.30g (0.01mol) 3-[2-(4-hydroxybutoxy)-1-[(2-hydroxyethoxy)methyl]ethoxy]-1-propanesulfonic acid (CAS No.: 735251-18-0, ) is added to the hydroxide solution of dihexadecyldimethylammonium ion, stirred for reaction for 10 to 15 minutes, and vacuum baked to remove the solvent to obtain 3# polyhydroxysulfonic acid quaternary ammonium salt.

[0060] (3) Preparation of water- and oxygen-blocking polyethylene composite materials

[0061] Table 1 Raw material addition amount of water-blocking and oxygen-blocking polyethylene composite material (unit: mass parts)

[0062]

[0063] 1) Preparation of Examples 1 to 4

[0064] S01, add montmorillonite to deionized water, stir at 50-60°C until the montmorillonite is fully dissolved, add quaternary ammonium salt of polyhydroxysulfonic acid, continue heating and stirring, and react for 3 hours;

[0065] S02, add hydroxylated glass fiber, stir and react at room temperature (25±2°C) for 3 hours;

[0066] S03, the product of step S02 is centrifuged, washed with deionized water, and dried to obtain an organic montmorillonite-glass fiber composite;

[0067] S04, blending polyethylene, ethylene-vinyl alcohol copolymer, the organic montmorillonite-glass fiber composite and the additives described in step S03, heating and melting at 180-230° C., extruding and granulating, to obtain the water-blocking and oxygen-blocking polyethylene composite material.

[0068] 2) Preparation method of comparative example 1

[0069] The difference between Comparative Example 1 and Example 1 is that octadecyltrimethylammonium bromide is used instead of polyhydroxysulfonic acid quaternary ammonium salt to prepare the polyethylene composite material.

[0070] S01, add montmorillonite to deionized water, stir at 50-60°C until the montmorillonite is fully dissolved, add octadecyltrimethylammonium bromide, continue heating and stirring, and react for 3 hours;

[0071] S02, add hydroxylated glass fiber, stir and react at room temperature (25±2°C) for 3 hours;

[0072] S03, the product of step S02 is centrifuged, washed with deionized water, and dried to obtain an organic montmorillonite-glass fiber composite;

[0073] S04, blending polyethylene, ethylene-vinyl alcohol copolymer, the organic montmorillonite-glass fiber composite described in step S03 and an additive, heating and melting at 180-230° C., extruding and granulating, and obtaining a polyethylene composite material.

[0074] 3) Preparation method of comparative example 2

[0075] The difference between Comparative Example 2 and Example 4 is that no hydroxylated glass fiber is added. The preparation method is as follows:

[0076] S01, add montmorillonite to deionized water, stir at 50-60°C until the montmorillonite is fully dissolved, add quaternary ammonium salt of polyhydroxysulfonic acid, continue heating and stirring, and react for 3 hours;

[0077] S02, the product of step S01 is centrifuged, washed with deionized water, and dried to obtain organic montmorillonite;

[0078] S03, blending polyethylene, ethylene-vinyl alcohol copolymer, the organic montmorillonite and the additives described in step S02, heating and melting at 180-230° C., extruding and granulating, to obtain a polyethylene composite material.

[0079] 4) Preparation method of comparative example 3

[0080] The difference between Comparative Example 3 and Example 4 is that no montmorillonite is added. The preparation method is as follows:

[0081] S01, dissolving quaternary ammonium polyhydroxysulfonate in deionized water, adding hydroxylated glass fiber, and stirring at room temperature (25±2°C) for 3 hours;

[0082] S02, the product of step S01 is centrifuged, washed with deionized water, and dried to obtain modified glass fiber;

[0083] S03, blending polyethylene, ethylene-vinyl alcohol copolymer, the modified glass fiber and additives described in step S02, heating and melting at 180-230° C., extruding and granulating, to obtain a polyethylene composite material.

[0084] 5) Preparation method of comparative example 4

[0085] The difference between Comparative Example 4 and Example 1 is that the amount of montmorillonite is increased from 8 parts by mass to 11 parts by mass.

[0086] 6) Preparation method of comparative example 5

[0087] The difference between Comparative Example 5 and Example 1 is that the glass fiber added in step S02 is not subjected to hydroxylation treatment.

[0088] S01, add montmorillonite to deionized water, stir at 50-60°C until the montmorillonite is fully dissolved, add quaternary ammonium salt of polyhydroxysulfonic acid, continue heating and stirring, and react for 3 hours;

[0089] S02, add glass fiber, stir at room temperature (25±2℃) for 3 hours;

[0090] S03, the product of step S02 is centrifuged, washed with deionized water, and dried to obtain an organic montmorillonite-glass fiber composite;

[0091] S04, blending polyethylene, ethylene-vinyl alcohol copolymer, the organic montmorillonite-glass fiber composite and the additives described in step S03, heating and melting at 180-230° C., extruding and granulating, to obtain the water-blocking and oxygen-blocking polyethylene composite material.

[0092] Table 2 Performance test of polyethylene composite materials prepared in Examples 1 to 4 and Comparative Examples 1 to 5

[0093]

[0094]

[0095] As shown in Table 2, the polyethylene composite materials in Examples 1 to 4 have excellent water and oxygen barrier properties, wherein the oxygen permeability under 0% RH conditions is less than 0.42 cm 3 / (m 2 ·24h·0.1MPa), the oxygen permeability under high humidity conditions is less than 0.9cm 3 / (m 2 ·24h·0.1MPa), water vapor transmission rate is less than 0.8g / (m 2 ·24h); in addition, its tensile properties and impact strength meet the requirements of use.

[0096] It can be seen from Comparative Example 1 and Example 1 that the polyethylene composite material prepared by using octadecyltrimethylammonium bromide instead of polyhydroxysulfonic acid quaternary ammonium salt has reduced water and oxygen barrier properties, and its tensile strength and impact strength are also significantly reduced. This is because the interaction between montmorillonite modified by octadecyltrimethylammonium bromide and hydroxylated glass fiber is small, and the montmorillonite-glass fiber composite is unstable, resulting in poor dispersion of glass fiber in the system, and poor barrier properties and mechanical properties.

[0097] It can be seen from Comparative Example 2 and Example 4 that when hydroxylated glass fiber is not added, the water and oxygen barrier properties of the composite material are significantly reduced. On the one hand, this is because the distribution regularity of the montmorillonite nanosheets is reduced, and on the other hand, it is because the density of the composite material is reduced due to the lack of hydrogen bonding between the hydroxyl glass fiber and EVOH; in addition, without the reinforcing effect of the glass fiber, the tensile strength and impact strength of the composite material are both reduced.

[0098] It can be seen from Comparative Example 3 and Example 4 that when montmorillonite is not added, the barrier effect of the nano-montmorillonite sheet is lost, and the oxygen barrier property of the composite material is significantly deteriorated and the water barrier property is reduced under high humidity conditions; at the same time, without the toughening effect of the nano-montmorillonite, the impact strength of the composite material is also reduced.

[0099] It can be seen from Comparative Example 4 and Example 1 that when the amount of montmorillonite continues to increase to 11 parts by mass, the barrier properties and mechanical properties deteriorate. This may be due to the agglomeration phenomenon when the amount of montmorillonite is large.

[0100] It can be seen from Comparative Example 5 and Example 1 that when the glass fiber is not hydroxylated, the water and oxygen barrier properties of the composite material decrease, and the tensile strength and impact strength also decrease significantly. This is because the -OH content of the surface of the glass fiber that has not been hydroxylated is low, the interaction force between the glass fiber and the modified montmorillonite is small, and the compatibility of the glass fiber itself with polyethylene is not good, resulting in instability of the dispersed phase in the system, and poor barrier properties and mechanical properties.

[0101] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A water-blocking and oxygen-blocking polyethylene composite material, characterized in that: The water-blocking and oxygen-blocking polyethylene composite material includes the following raw material components calculated in parts by weight:

2. The water-blocking and oxygen-blocking polyethylene composite material according to claim 1, characterized in that: The hydroxylated glass fiber is obtained by heating the glass fiber in a strong acid.

3. The water-blocking and oxygen-blocking polyethylene composite material according to claim 1, characterized in that: The general structural formula of the polyhydroxysulfonic acid quaternary ammonium salt is shown in formula (I): wherein the values ​​of n1, n2, n3 and n4 of the alkyl chain on the quaternary ammonium cation are independently selected from 1 to 18 and are not 1 at the same time; the anion containing R in formula (I) is 4. The water-blocking and oxygen-blocking polyethylene composite material according to claim 1, characterized in that: The preparation method of the polyhydroxysulfonic acid quaternary ammonium salt comprises the following steps: S1, dissolving a halide salt of a quaternary ammonium compound in a solvent, exchanging the halide anion for a hydroxide anion through a hydroxide exchange column to form a hydroxide containing a quaternary ammonium cation; S2, adding polyhydroxy sulfonic acid in an equimolar amount to the hydroxide containing quaternary ammonium cations, stirring for neutralization reaction, and vacuum baking to remove the solvent to obtain the polyhydroxy sulfonic acid quaternary ammonium salt.

5. The water-blocking and oxygen-blocking polyethylene composite material according to claim 3, characterized in that: The quaternary ammonium cation is a mixture of one or more of dodecyltrimethylammonium ion, tetradecyltrimethylammonium ion, hexadecyltrimethylammonium ion, octadecyltrimethylammonium ion, dioctyldimethylammonium ion, didecyldimethylammonium ion, didodecyldimethylammonium ion, ditetradecyldimethylammonium ion, dihexadecyldimethylammonium ion and dioctadecyldimethylammonium ion.

6. The water-blocking and oxygen-blocking polyethylene composite material according to claim 4, characterized in that: The polyhydroxy sulfonic acid is a mixture of one or more of 1,2-dihydroxyethanesulfonic acid, 2-(diethanolamino)ethanesulfonic acid, and 3-[2-(4-hydroxybutoxy)-1-[(2-hydroxyethoxy)methyl]ethoxy]-1-propanesulfonic acid.

7. The water-blocking and oxygen-blocking polyethylene composite material according to claim 1, characterized in that: The auxiliary agent includes a mixture of one or more of an antioxidant, an antistatic agent, a compatibilizer, and a toughening agent.

8. The method for preparing the water-blocking and oxygen-blocking polyethylene composite material according to any one of claims 1 to 7, characterized in that: The steps include: S01, adding montmorillonite to deionized water, heating and stirring until the montmorillonite is fully dissolved, adding quaternary ammonium salt of polyhydroxysulfonic acid and continuing heating to react; S02, add hydroxylated glass fiber, and stir to react at room temperature; S03, the product of step S02 is centrifuged, washed, and dried to obtain an organic montmorillonite-glass fiber composite; S04, blending polyethylene, ethylene-vinyl alcohol copolymer, the organic montmorillonite-glass fiber composite and the additives in step S03, heating and melting, and extruding and granulating to obtain the water-blocking and oxygen-blocking polyethylene composite material.

9. The method for preparing the water-blocking and oxygen-blocking polyethylene composite material according to claim 8, characterized in that: The heating temperature in step S01 is 50-60°C, the room temperature in step S02 is 10-40°C, and the heating temperature in step S04 is 180-230°C.

10. The method for preparing the water-blocking and oxygen-blocking polyethylene composite material according to claim 8, characterized in that: The heating reaction time in step S01 is 2 to 4 hours, and the stirring reaction time in step S02 is 2 to 4 hours.

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