CN115923304A

CN115923304A - Processing method for preparing single polyethylene composite material

Info

Publication number: CN115923304A
Application number: CN202211596276.1A
Authority: CN
Inventors: 汪来胜; 张海斌; 张廷戴
Original assignee: Guangzhou Novel Packaging Co ltd
Current assignee: Guangzhou Novel Packaging Co ltd
Priority date: 2022-12-13
Filing date: 2022-12-13
Publication date: 2023-04-07

Abstract

The invention discloses a processing method for preparing a single polyethylene composite material. In the process of preparing the polyethylene composite material, the longitudinally stretched polyethylene film and the high-moisture-resistance aluminum-plated polyethylene film are firstly compounded, and then are compounded with the high-moisture-resistance polyethylene film for the second time, the high-moisture-resistance aluminum-plated polyethylene film is prepared into an intermediate barrier layer of the polyethylene composite material, and the polyethylene composite material obtained by compounding the high-moisture-resistance aluminum-plated polyethylene film and the high-moisture-resistance polyethylene film has excellent gas-liquid barrier property and high barrier property.

Description

Processing method for preparing single polyethylene composite material

Technical Field

The invention relates to the technical field of polyethylene compounding, in particular to a processing method for preparing a single polyethylene material composite film.

Background

The flexible package refers to a package in which the shape of a container is changed after filling or removing contents, and various bags, boxes, sleeves, envelopes, and the like made of plastic films and composites thereof are flexible packages, and can be widely used in the field of packaging of foods, cosmetics, medicines, and the like.

The traditional flexible packaging film preparation and processing method is generally formed by compounding and processing films of various different materials, the polyethylene film and the polyester film are used as base materials and are compounded with PE, PP or BOPP, so that a packaging composite film structure is obtained, and the packaging composite film prepared by adopting the traditional flexible packaging film can protect packaging contents, avoid pollutants and infiltration and simultaneously prevent the packaging contents from seeping. However, the packaging composite film processed by the traditional preparation method has the defects of low barrier property, poor gas barrier property, high oxygen permeability and low heat sealing strength, and cannot effectively prevent the permeation of external water vapor and gas, and part of gas can permeate the packaging composite film to enter the packaging bag to cause bacterial reproduction and cause the deterioration of the contents in the packaging bag. And the packaging composite film processed by the traditional preparation method is formed by compounding a plurality of different material structure layers, and when the packaging composite film is recycled, different material layers need to be stripped, so that the complexity of the recycling process is increased, and the recycling of the packaging composite film is not facilitated.

In the prior art, in order to increase the barrier property of a packaging composite film, a polyvinylidene chloride (PVDC) coating film is compounded during composite processing and preparation, although the effect of blocking oxygen and water vapor can be achieved, the polyvinylidene chloride (PVDC) coating film needs special equipment and cannot be melted, granulated and recycled, and wastes can generate substances which are toxic and harmful to human beings and the surrounding environment, such as hydrogen chloride and dioxin, during incineration, so that the environment is damaged, and the life health of the human beings is threatened.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art and provides a processing method which is suitable for compounding a longitudinally stretched polyethylene film, a high-humidity-resistant aluminum-plated polyethylene film and a high-humidity-resistant polyethylene film, compounding the longitudinally stretched polyethylene film and the high-humidity-resistant aluminum-plated polyethylene film for the first time and then compounding the longitudinally stretched polyethylene film and the high-humidity-resistant aluminum-plated polyethylene film for the second time, wherein the high-humidity-resistant aluminum-plated polyethylene film can be made into a middle barrier layer of a polyethylene composite material, and the polyethylene composite material obtained by compounding the high-humidity-resistant aluminum-plated polyethylene film and the high-humidity-resistant polyethylene film has excellent gas-liquid barrier property, high barrier property, excellent heat sealing property, moderate friction coefficient, no adhesion and no slippage during cutting and is very suitable for a high-speed packaging production line.

In order to solve the technical problems, the invention adopts the following technical scheme:

the invention provides a processing method for preparing a single polyethylene composite material, which comprises the processing method for processing and preparing the polyethylene composite material, wherein the polyethylene composite material is prepared by processing and compounding a longitudinally stretched polyethylene film, a polyurethane ink layer, a first layer of two-component polyurethane adhesive, a high-humidity aluminum-plated polyethylene film, a second layer of two-component polyurethane adhesive and a high-oxygen-resistance polyethylene film, and the processing method specifically comprises the following steps:

step S1) intaglio printing treatment: loading the prepared longitudinal stretching polyethylene film with the thickness of 25 micrometers on a first discharging shaft of a gravure printing machine, sending the longitudinal stretching polyethylene film with the thickness of 25 micrometers to each printing color unit through the first discharging shaft of the printing machine, performing gravure printing by taking the longitudinal stretching polyethylene film as a base material, printing a polyurethane ink layer on the surface of the longitudinal stretching polyethylene film, controlling the viscosity of the ink to be 13-17 viscosity/Pa.s, setting the tension required by a first unwinding roller of the printing machine for unwinding the longitudinal stretching polyethylene film to be 100N, and setting the winding tension after printing to be 120N;

step S2) first-pass composite processing: loading the 25 mu M-thick longitudinally-stretched polyethylene film printed in the step 1 into a second discharging shaft end, wherein the tension required by discharging the 25 mu M-thick longitudinally-stretched polyethylene film by using the second discharging shaft is 120N, loading the prepared 40 mu M-thick high-moisture-resistance aluminized polyethylene film into a third discharging shaft end, the tension required by discharging the 40 mu M-thick high-moisture-resistance aluminized polyethylene film by using the third discharging shaft end is 140N, feeding the 25 mu M-thick longitudinally-stretched polyethylene film into a first gluing system through the second discharging shaft end, coating a first layer of double-component polyurethane adhesive on the inner surface of the processing surface of the 25 mu M-thick longitudinally-stretched polyethylene film by using a first gluing roller of the first gluing system, the coated 25 mu M-thick longitudinally-stretched polyethylene film enters a drying oven for drying, organic solvent in the first layer of bicomponent polyurethane adhesive is volatilized, the 25 mu M-thick longitudinally-stretched polyethylene film enters three drying tunnels in the drying oven for drying, the temperatures of the three drying tunnels are respectively 50 ℃, 60 ℃ and 70 ℃, the longitudinally-stretched polyethylene film dried by the three drying tunnels and the processing surface of the high-humidity aluminum-plated polyethylene film are subjected to hot-pressing compounding to form a semi-finished composite film, the pressure required in the hot-pressing process of a hot-pressing compounding guide roller is 0.35Mpa, the compounding speed is 90M/min, the gluing mesh of the first glue coating roller is a 110 x 75 gravure mesh roller, the gluing amount is 3.2-3.5g/, and the tension required for rolling the semi-finished composite film is 200N;

step S3) second-pass composite processing: loading the first-pass compounded semi-finished composite film (25 mu M thick longitudinally-stretched polyethylene film/40 mu M thick high-resistance wet-plated aluminum-plated polyethylene film) into a fourth discharging shaft end, wherein the tension required by discharging the semi-finished composite film by a fourth discharging shaft is 160N, loading the prepared 70 mu M thick high-resistance oxygen-plated polyethylene film into a fifth discharging shaft end, the tension required by discharging the 70 mu M thick high-resistance oxygen-plated polyethylene film by a fifth discharging shaft is 140N, feeding the semi-finished composite film (25 mu M thick longitudinally-stretched polyethylene film/40 mu M thick high-resistance wet-plated aluminum-plated polyethylene film) into a second gluing system by the fourth discharging shaft, coating a second layer of polyurethane adhesive on the inner surface of the 40 mu M thick high-resistance wet-plated aluminum-plated polyethylene film by a second glue coating roller of the second gluing system, the coated semi-finished composite film (25 mu M thick longitudinally stretched polyethylene film/40 mu M thick high-resistance aluminum-plated polyethylene film) enters an oven for drying, organic solvent in the second layer of double-component polyurethane adhesive is volatilized, the semi-finished composite film enters three drying channels in the oven for drying, the temperatures of the three drying channels are respectively 50 ℃, 60 ℃ and 70 ℃, the semi-finished composite film (25 mu M thick longitudinally stretched polyethylene film/40 mu M thick high-resistance aluminum-plated polyethylene film) coming out of the drying channels and the inner surface of the processing surface of the high-resistance oxygen polyethylene film are subjected to hot-pressing compounding to form a polyethylene composite material, the pressure required by the hot-pressing compounding guide roller of the polyethylene composite material in the hot-pressing process is 0.35MPa, the compounding speed is 90M/min, the glue coating mesh of the second glue coating roller is a 110 x 75 glue coating mesh roller, the glue coating amount is 3.2-3.5 g/square meter, the tension required for winding up the polyethylene composite material is 240N.

Aiming at the further improvement of the technical scheme, the type of the first layer of two-component polyurethane adhesive and the second layer of two-component polyurethane adhesive used in the steps S2) and S3) is the type of 'XH-66F/XH-K75', and the proportion of the two-component polyurethane adhesive is as follows: host XH-66F: curing agent XH-K75: ethyl acetate solvent = 20.

Aiming at further improvement of the technical scheme, the longitudinally stretched polyethylene film in the step S1) is made of a heat sealing layer, an intermediate layer and a corona layer, wherein the heat sealing layer accounts for 30%, the intermediate layer accounts for 40%, and the corona layer accounts for 30%; the heat sealing layer consists of 5-33% of medium-density metallocene and 5-80% of low-pressure high-density polyethylene resin; the intermediate layer is composed of 100% high tensile metallocene; the corona layer is composed of 5-33% of medium-density metallocene, 10-75% of low-pressure high-density metallocene, 0.5-2% of an opening agent and 0.5-2% of a slipping agent.

Aiming at the further improvement of the technical scheme, the longitudinally stretched polyethylene film in the step S1) is prepared by the following processing steps:

step S11) weighing and mixing the components according to the corresponding percentage of each layer in the longitudinally stretched polyethylene film, adding the mixture obtained by mixing the layers into three charging barrels of a corresponding WH film blowing machine to respectively prepare the mixture of the heat-sealing layer, the mixture of the middle layer and the mixture of the corona layer, and plasticizing the mixture into a melt by high temperature heating below the three charging barrels of the WH film blowing machine, wherein the high temperature heating temperature is 180-250 ℃;

step S12) extruding the melt through a three-layer co-extrusion film blowing die head of a WH film blowing machine to obtain a molten film, wherein the extrusion speed is 550-600Kg/h, blowing the molten film through the WH film blowing machine to form a film bubble, and then cooling;

step S13), flattening the cooled and formed film, feeding the film into MDO stretching equipment of a WH film blowing machine under the action of a rotary drawing roller to carry out a stretching process, wherein the temperature during longitudinal stretching is 90-100 ℃, the stretching ratio of the film is 5, and carrying out heat setting at 150 ℃ after stretching;

and S14), performing corona treatment on the stretched film, cutting edges, and rolling to obtain the longitudinally stretched polyethylene film.

Aiming at further improvement of the technical scheme, the high-resistance wet-plating aluminum-plated polyethylene film in the step S2) is prepared by high-temperature fusion of a first layer A particle layer, a second layer B particle layer and a third layer C particle layer, wherein the proportion of the first layer A particle layer is 30%, and the proportion of the second layer B particle layer is 40%; the proportion of the third layer of particles C is 30 percent, wherein the first layer of particles A is composed of 100 percent of linear medium density polyethylene resin; the second layer of particle B consists of 80 to 85 percent of low-pressure high-density polyethylene resin and 10 to 25 percent of high-pressure low-density polyethylene resin; the third layer of particle C consists of 80-81% of medium density metallocene polyethylene, 14-25% of high pressure low density polyethylene resin, 0.5-2% of opening agent and 0.5-2% of slipping agent.

Aiming at the further improvement of the technical scheme, the high-resistance wet-plating aluminum-plated polyethylene film in the step S2) is prepared by the following processing steps:

step S21) weighing and mixing the components according to the corresponding percentage of each layer in the high-humidity-resistance aluminized polyethylene film, and then respectively adding the components into three charging barrels of an extruder to respectively prepare a mixture of a first layer A particle layer, a mixture of a second layer B particle layer and a mixture of a third layer C particle layer;

step S22), carrying out high-temperature melting on the mixture in the three charging barrels in the step S21 through a high-temperature heating and melting device of an extruder to form a tube blank, wherein the temperature required by the high-temperature melting is 180-300 ℃;

step S23) stretching the tube blank, extruding the tube blank from the center of a die head of an extruder, compressing air to blow the tube blank into film bubbles, and cooling and shaping the film bubbles through an air ring to obtain a film;

and S24) feeding the film prepared in the step S23 into an aluminum plating machine, carrying out double corona vacuum evaporation on the film, and carrying out double corona vacuum evaporation treatment to obtain the high-humidity-resistance polyethylene film.

The water vapor transmission rate of the high-resistance wet-plating aluminum polyethylene film prepared by the steps S21) to S24) is 0.5-0.8 g/(m) ² ·24h)。

Aiming at the further improvement of the technical scheme, the high oxygen resistant polyethylene film in the step S3) is formed by co-extruding a polyamide layer, a first high density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer, a second bonding layer, a second high density polyethylene layer and a polyethylene layer, wherein the polyamide layer accounts for 25%, the first high density polyethylene layer accounts for 15%, the first bonding layer accounts for 5%, the ethylene-vinyl alcohol copolymer layer accounts for 10%, the second bonding layer accounts for 5%, the second high density polyethylene layer accounts for 15%, and the polyethylene layer accounts for 25%.

Aiming at the further improvement of the technical scheme, the polyamide layer of the high-oxygen-resistance polyethylene film in the step S3) is composed of 100% of polyamide; the first high density polyethylene layer consists of 70-75% of linear low density polyethylene and 20-30% of high pressure low density polyethylene; the first bonding layer is composed of 40-50% of bonding resin and 50-60% of linear low-density polyethylene; the ethylene-vinyl alcohol copolymer layer consists of 20-35% polymerized vinyl acetate and 74-76% polymerized ethylene; the second bonding layer is composed of 40-50% bonding resin and 50-60% linear low density polyethylene; said second high density polyethylene layer consisting of 70-75% linear low density polyethylene and 20-30% high pressure low density polyethylene; the polyethylene layer consists of 30-40% of metallocene polyethylene, 30-32% of linear low density polyethylene, 30-34% of high pressure low density polyethylene, 0.5-2% of an opening agent and 0.5-2% of a slipping agent.

Aiming at the further improvement of the technical scheme, the high-oxygen-resistance polyethylene film in the step S3) is prepared by the following processing steps:

step S31) weighing and mixing the components according to the corresponding percentages of the components in each layer in the high-oxygen-resistance polyethylene film, and adding a mixture obtained by mixing the components in each layer into seven charging barrels of an extruder;

step S32) mixing the mixture obtained in the step S1 into seven material cylinders of an extruder, heating and melting the mixture into a melt through a high-temperature heating and melting device of the extruder at the high-temperature of 200-300 ℃, respectively preparing a polyamide layer, a first high-density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer, a second bonding layer, a second high-density polyethylene layer and seven polyethylene layers, co-extruding the mixture through the extruder, and then converging and heating the mixture in a T-shaped die head after circulating through a runner distributor;

step S33), the resin flowing out after the confluence and heating of the T-shaped die is coated with a film, the film is cooled by a cooling roller and shaped to obtain the high-oxygen-resistance polyethylene film, and the density of the obtained high-oxygen-resistance polyethylene film is 1.12g/cm ³ The oxygen transmission capacity of the high-oxygen-resistance polyethylene film is less than or equal to 5.0cm < 3 >/(. Square meter. 24 h. 0.1 MPa), the friction coefficient of the high-oxygen-resistance polyethylene film is 0.44-0.48, the cooling temperature is 15-25 ℃, the temperature required by heating the T-shaped die head is 250-300 ℃, and the cooling temperature is 15-25 ℃;

and S34) trimming the high-oxygen-resistance polyethylene film, and winding by a winding machine.

Aiming at the further improvement of the technical proposal, the thickness of the ethylene-vinyl alcohol copolymer layer is 7 μm, and the melt flow index of the polymerized ethylene in the ethylene-vinyl alcohol copolymer layer is 6-12 g/10min.

Compared with the prior art, the scheme of the invention at least comprises the following beneficial effects:

(1) The processing method for preparing the polyethylene composite material comprises gravure printing treatment, first-time compounding treatment and second-time compounding treatment, wherein a longitudinally stretched polyethylene film is used as a base material to perform gravure printing, the surface of the longitudinally stretched polyethylene film coated with a first layer of double-component polyurethane adhesive is used for forming a semi-finished composite film, the longitudinally stretched polyethylene film and a high-moisture-resistance aluminum-plated polyethylene film are subjected to hot-pressing compounding by using a hot-pressing compounding guide roller, the longitudinally stretched polyethylene film and the high-moisture-resistance aluminum-plated polyethylene film which are compounded for the first time are subjected to gluing, and the longitudinally stretched polyethylene film and the high-moisture-resistance aluminum-plated polyethylene film are subjected to second-time compounding to form the polyethylene composite material. In the process of preparing the polyethylene composite material, the longitudinally stretched polyethylene film and the high-moisture-resistance aluminized polyethylene film are firstly compounded, then are compounded with the high-oxygen-resistance polyethylene film for the second time, the two-component polyurethane adhesive is used for bonding the longitudinally stretched polyethylene film with the thickness of 25 mu m, the longitudinally stretched polyethylene film with the thickness of 25 mu m is dried in a drying oven, the organic solvent in the two-component polyurethane adhesive is volatilized, the solvent-free compounding is realized, the polyethylene composite material is conveniently prepared by adopting a compounding mode, the separation between the film layers is relatively easy to realize during the recycling, and each film layer can be repeatedly utilized after being separated and recycled, thereby being beneficial to the environment and saving the resources. The invention makes the high-wet-resistance aluminized polyethylene film into the middle barrier layer of the polyethylene composite material, and the polyethylene composite material obtained by compounding the high-wet-resistance aluminized polyethylene film and the high-wet-resistance polyethylene film has excellent gas-liquid barrier property, high barrier property, excellent heat sealing property and moderate friction coefficient, can not generate adhesion and slip when being cut off, and is very suitable for a high-speed packaging production line.

(2) The high-resistance wet-plating aluminum-plated polyethylene film is prepared by high-temperature fusion of a first layer A particle layer, a second layer B particle layer and a third layer C particle layer, wherein the first layer A particle layer accounts for 30%, and the second layer B particle layer accounts for 40%; the proportion of the third layer of particles C is 30 percent, wherein the first layer of particles A is composed of 100 percent of linear medium density polyethylene resin; the second layer of particle B consists of 80 to 85 percent of low-pressure high-density polyethylene resin and 10 to 25 percent of high-pressure low-density polyethylene resin; the third layer of particle C consists of 80-81% of medium density metallocene polyethylene, 14-25% of high pressure low density polyethylene resin, 0.5-2% of opening agent and 0.5-2% of slipping agent. The components of each layer structure in the high-humidity-resistance aluminized polyethylene film are mixed and then respectively added into three charging barrels of an extruder to respectively prepare a mixture of a first layer A particle layer, a mixture of a second layer B particle layer and a mixture of a third layer C particle layer, the mixtures in the three charging barrels are subjected to high-temperature melting through a high-temperature heating melting device of the extruder to form a tube blank, the tube blank is stretched and then extruded from the center of a die head of the extruder and compressed with air, so that the tube blank is blown and expanded into film bubbles, meanwhile, the film bubbles are cooled and shaped through an air ring to prepare the film, the film prepared in the step S23 is sent into an aluminizing machine, the film is subjected to double corona vacuum evaporation, and the high-humidity-resistance polyethylene film is obtained through double corona vacuum evaporation. The high-moisture-resistance aluminized polyethylene film prepared by the preparation steps has the water vapor transmission rate of 0.5-0.8 g/square meter 24 h. Compared with the common linear low-density polyethylene, the polyethylene composite material prepared by the invention adopts the high-humidity-resistance aluminum-plated polyethylene film to compound, so that the barrier property of the polyethylene composite material can be greatly improved.

(3) The high oxygen resistant polyethylene film is formed by co-extruding a polyamide layer, a first high density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer, a second bonding layer, a second high density polyethylene layer and a polyethylene layer, wherein the polyamide layer accounts for 25 percent, the first high density polyethylene layer accounts for 15 percent, the first bonding layer accounts for 5 percent, the ethylene-vinyl alcohol copolymer layer accounts for 10 percent, the second bonding layer accounts for 5 percent, the second high density polyethylene layer accounts for 15 percent and the polyethylene layer accounts for 25 percent,the polyamide layer of the high-oxygen-resistant polyethylene film consists of 100 percent of polyamide; the first high density polyethylene layer consists of 70-75% linear low density polyethylene and 20-30% high pressure low density polyethylene; the first bonding layer is composed of 40-50% of bonding resin and 50-60% of linear low density polyethylene; the ethylene-vinyl alcohol copolymer layer is composed of 20-35% polymerized vinyl acetate and 74-76% polymerized ethylene; the second bonding layer is composed of 40-50% of bonding resin and 50-60% of linear low-density polyethylene; the second high density polyethylene layer consists of 70-75% linear low density polyethylene and 20-30% high pressure low density polyethylene; the polyethylene layer is composed of 30-40% of metallocene polyethylene, 30-32% of linear low density polyethylene, 30-34% of high pressure low density polyethylene, 0.5-2% of opening agent and 0.5-2% of slipping agent. Extruding all layers by an extruder in a co-extrusion mode, then circulating the layers through a flow channel distributor, converging and heating the layers in a T-shaped die head, laminating the resin flowing out after converging and heating the layers by the T-shaped die head, cooling the resin by a cooling roller and shaping the resin to obtain the high-oxygen-resistance polyethylene film, wherein the density of the obtained high-oxygen-resistance polyethylene film is 1.12g/cm ³ The oxygen transmission capacity of the high oxygen resistant polyethylene film is less than or equal to 5.0cm ³ The friction coefficient of the high oxygen resistant polyethylene film is 0.44 to 0.48 per square meter (24 h.0.1 MPa). The high-oxygen-resistant polyethylene film prepared by the invention has extremely high barrier property, excellent heat sealing property and moderate friction coefficient, can not generate adhesion and slippage when being cut off, and is suitable for high-speed packaging production lines.

Drawings

FIG. 1 is a schematic flow chart of the present invention for processing and preparing a polyethylene composite material;

FIG. 2 is a schematic structural view of a polyethylene composite according to the present invention;

FIG. 3 is a spectrum of a longitudinally stretched polyethylene film of the polyethylene composite according to the present invention;

FIG. 4 is a spectrum diagram of the polyethylene composite material of the present invention for identifying a high-resistance aluminum-plated polyethylene film;

FIG. 5 is a spectrum diagram of the polyethylene composite material of the present invention for identifying a high oxygen resistant polyethylene film.

In the figure, a longitudinally stretched polyethylene film 1, a polyurethane ink layer 2, a first layer of two-component polyurethane adhesive 3, a high-humidity aluminized polyethylene film 4, a second layer of two-component polyurethane adhesive 5 and a high-oxygen-resistance polyethylene film 6.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1-2, the present invention provides a processing method for preparing a single polyethylene composite material, which comprises a processing method for processing and preparing a polyethylene composite material, wherein the polyethylene composite material is prepared by processing and compounding a longitudinally stretched polyethylene film 1, a polyurethane ink layer 2, a first layer of two-component polyurethane adhesive 3, a high-humidity aluminum-plated polyethylene film 4, a second layer of two-component polyurethane adhesive 5, and a high-oxygen-resistant polyethylene film 6, and the processing method specifically comprises the following steps:

step S1) intaglio printing treatment: loading the prepared longitudinal stretching polyethylene film 1 with the thickness of 25 micrometers on a first discharging shaft of a gravure printing machine, sending the longitudinal stretching polyethylene film 1 with the thickness of 25 micrometers to each printing color unit through the first discharging shaft of the printing machine, carrying out gravure printing by taking the longitudinal stretching polyethylene film 1 as a base material, printing a polyurethane ink layer 2 on the surface of the longitudinal stretching polyethylene film 1, controlling the viscosity of the ink to be 13-17 viscosity/Pa.s, wherein the tension required by a first unwinding roller of the printing machine for unwinding the longitudinal stretching polyethylene film 1 is 100N, and the winding tension after printing is 120N;

step S2) first-pass composite processing: loading the 25 mu M-thick longitudinally-stretched polyethylene film 1 printed in the step 1 into a second discharging shaft end, wherein the tension required by the second discharging shaft to discharge the 25 mu M-thick longitudinally-stretched polyethylene film 1 is 120N, loading the prepared 40 mu M-thick high-resistance wet-plating aluminum-plated polyethylene film 4 into a third discharging shaft end, the tension required by the third discharging shaft to discharge the 40 mu M-thick high-resistance wet-plating aluminum-plated polyethylene film 4 is 140N, sending the 25 mu M-thick longitudinally-stretched polyethylene film 1 into a first gluing system through the second discharging shaft end, coating a first layer of two-component polyurethane adhesive 3 on the inner surface of the 25 mu M-thick longitudinally-stretched polyethylene film 1 by a first gluing roller of the first gluing system, the coated 25 mu M-thick longitudinally-stretched polyethylene film 1 enters an oven for drying, organic solvent in a first layer of double-component polyurethane adhesive 3 is volatilized, the 25 mu M-thick longitudinally-stretched polyethylene film 1 enters three drying channels in the oven for drying, the temperatures of the three drying channels are respectively 50 ℃, 60 ℃ and 70 ℃, the longitudinally-stretched polyethylene film 1 dried by the three drying channels and the processing surface of a high-resistance wet-plating aluminum polyethylene film 4 are subjected to hot-pressing compounding to form a semi-finished product composite film, the pressure required by the hot-pressing compounding guide roller in the hot-pressing process is 0.35MPa, the compounding speed is 90M/min, the gluing mesh of the first gluing roller is a 110 x 75 gravure mesh roller, the gluing amount is 3.2-3.5/g/square meter, and the tension required by rolling the semi-finished product composite film is 200N;

step S3) second-pass composite processing: loading the first-time compounded semi-finished composite film (a high-moisture-resistance aluminized polyethylene film 4 with the thickness of 1/40 mu M of a longitudinally stretched polyethylene film with the thickness of 25 mu M) into a fourth discharging shaft end, wherein the tension required for discharging the semi-finished composite film by the fourth discharging shaft is 160N, loading the prepared high-oxygen-resistance polyethylene film 6 with the thickness of 70 mu M into a fifth discharging shaft end, the tension required for discharging the high-oxygen-resistance polyethylene film 6 with the thickness of 70 mu M by the fifth discharging shaft is 140N, feeding the semi-finished composite film (the high-moisture-resistance aluminized polyethylene film 4 with the thickness of 1/40 mu M of the longitudinally stretched polyethylene film with the thickness of 25 mu M) into a second gluing system by the fourth discharging shaft, coating a second layer of bicomponent polyurethane adhesive 5 on the inner surface of the high-moisture-resistance aluminized polyethylene film 4 with the thickness of 40 mu M by a second gluing roller of the second gluing system, the coated semi-finished composite film (a high-wet-resistance aluminized polyethylene film 4 with the thickness of 1/40 mu M of a longitudinal stretched polyethylene film with the thickness of 25 mu M) enters an oven for drying, organic solvent in a second layer of double-component polyurethane adhesive 5 is volatilized, the semi-finished composite film enters three drying channels in the oven for drying, the temperature of the three drying channels is 50 ℃, 60 ℃ and 70 ℃, the semi-finished composite film (the high-wet-resistance aluminized polyethylene film 4 with the thickness of 1/40 mu M of the longitudinal stretched polyethylene film with the thickness of 25 mu M) coming out of the drying channels and the inner surface of the processing surface of the high-oxygen-resistance polyethylene film 6 are subjected to hot-pressing compounding to form a polyethylene composite material, the pressure required by the hot-pressing compounding guide roller of the polyethylene composite material in the hot-pressing process is 0.35Mpa, the compounding speed is 90M/min, the adhesive mesh on the second glue-coated roller is a 110 x 75 gravure mesh roller, the gluing amount is 3.2-3.5 g/square meter, and the tension required for rolling the polyethylene composite material is 240N.

Wherein, the 25 μm-thick longitudinally stretched polyethylene film 1 prepared by the invention can be abbreviated as 25MDOPE, the 40 μm-thick high-resistance wet-plating aluminum polyethylene film 4 can be abbreviated as 40VMPE, and the 70 μm-thick high-resistance oxygen polyethylene film 6 can be abbreviated as 70EVE.

In the process of preparing the polyethylene composite material, the longitudinally stretched polyethylene film 1 and the high-moisture-resistance aluminum-plated polyethylene film 4 are firstly compounded for the first time, and then are compounded with the high-oxygen-resistance polyethylene film 6 for the second time. The polyethylene composite material takes a longitudinally stretched polyethylene film 1 as an outer layer, takes a high-humidity-resistance aluminized polyethylene film 4 as a middle barrier layer of the polyethylene composite material, and takes a high-oxygen-resistance polyethylene film 6 as an inner layer of the polyethylene composite material. The polyethylene composite material obtained by compounding the high-humidity-resistance aluminized polyethylene film 4 and the high-oxygen-resistance polyethylene film 6 has the advantages of excellent gas-liquid barrier property, high barrier property, excellent heat sealing property, moderate friction coefficient, no adhesion and slippage when being cut off, and is very suitable for a high-speed packaging production line. The multilayer composite film using polyethylene as a single material can meet the requirement of printing, and has good barrier property, heat sealing property and formability.

In the process of preparing the polyethylene composite material, the type of the first layer of the two-component polyurethane adhesive 3 and the type of the second layer of the two-component polyurethane adhesive 5 are the two-component polyurethane adhesive with the type of XH-66F/XH-K75, and the proportion of the two-component polyurethane adhesive is as follows: host XH-66F: curing agent XH-K75: the adhesive comprises the following components in parts by weight of ethyl acetate solvent =20, 3.8, 25-32% of working solution concentration of a two-component polyurethane adhesive, and 15 ± 2 seconds of viscosity of the two-component polyurethane adhesive, wherein the viscosity of the two-component polyurethane adhesive is measured by a 3# observation cup at 25 ℃ for a specific working solution concentration.

The longitudinally stretched polyethylene film 1 is prepared from a heat sealing layer, a middle layer and a corona layer, wherein the heat sealing layer accounts for 30 percent, the middle layer accounts for 40 percent, the corona layer accounts for 30 percent, and the heat sealing layer consists of 5-33 percent of medium-density metallocene and 5-80 percent of low-pressure high-density polyethylene resin; the middle layer is composed of 100% high tensile metallocene; the corona layer is composed of 5-33% of medium-density metallocene, 10-75% of low-pressure high-density metallocene, 0.5-2% of opening agent and 0.5-2% of slipping agent. In particular, the longitudinally stretched polyethylene film 1 is prepared by the following processing steps:

step S11) weighing and mixing the components according to the corresponding percentage of each layer in the longitudinally stretched polyethylene film 1, adding the mixture obtained by mixing each layer into three charging barrels of a corresponding WH film blowing machine to respectively prepare the mixture of the heat-sealing layer, the mixture of the middle layer and the mixture of the corona layer, and plasticizing the mixture into a melt by high-temperature heating below the three charging barrels of the WH film blowing machine, wherein the high-temperature heating temperature is 180-250 ℃;

and S14), performing corona treatment on the stretched film, cutting edges, and rolling to obtain the longitudinally stretched polyethylene film 1.

The middle layer of the longitudinally stretched polyethylene film 1 is provided with 100 percent of high-stretching metallocene composition, the heat sealing layer is provided with 5 to 33 percent of medium-density metallocene and 5 to 80 percent of low-pressure high-density polyethylene resin, the density of the film can be increased by arranging the low-pressure high-density polyethylene resin, and the heat resistance of the longitudinally stretched polyethylene film 1 is further increased, in the preparation method of the longitudinally stretched polyethylene film 1, an MDO stretching equipment process is adopted according to the raw material formula of each layer in the film, so that the film blown by a WH film blowing machine can be longitudinally stretched 5 times on the MDO stretching equipment, and when the longitudinally stretched polyethylene film 1 with the thickness of 100 mu m is specifically realized, the longitudinally stretched polyethylene film 1 with the thickness of 25 mu m is changed into the longitudinally stretched polyethylene film 1 with the thickness of 25 mu m after the longitudinally stretched polyethylene film 1 with the thickness of 100 mu m is subjected to 5 times of stretching ratio by the MDO stretching equipment. The stretched longitudinally stretched polyethylene film 1 has certain mechanical properties due to the change of molecular orientation, and the stretched longitudinally stretched polyethylene film 1 has excellent mechanical properties and transparency, so that the longitudinally stretched polyethylene film is more suitable for being used as a printing layer material.

The high-humidity-resistance aluminized polyethylene film 4 is prepared by high-temperature fusion of a first layer A particle layer, a second layer B particle layer and a third layer C particle layer, wherein the first layer A particle layer accounts for 30%, and the second layer B particle layer accounts for 40%; the proportion of the third layer of particles C is 30 percent, and the first layer of particles A is composed of 100 percent of linear medium density polyethylene resin; the second layer of particle B consists of 80 to 85 percent of low-pressure high-density polyethylene resin and 10 to 25 percent of high-pressure low-density polyethylene resin; the third layer of particle C consists of 80-81% of medium density metallocene polyethylene, 14-25% of high pressure low density polyethylene resin, 0.5-2% of opening agent and 0.5-2% of slipping agent. In specific implementation, the high-humidity-resistance aluminized polyethylene film 4 is prepared by the following processing steps:

step S21) weighing and mixing the components according to the corresponding percentage of each layer in the high-humidity-resistance aluminized polyethylene film 4, and then respectively adding the components into three charging barrels of an extruder to respectively prepare a mixture of a first layer A particle layer, a mixture of a second layer B particle layer and a mixture of a third layer C particle layer;

The high-humidity aluminized polyethylene film 4 prepared by the steps S21) to S24) has the water vapor transmission rate of 0.5-0.8 g/(m) ² ·24h)。

The third layer C particle layer adopts 81% of medium density metallocene polyethylene, the 81% of medium density metallocene polyethylene has strong pollution resistance and good sealing effect, the sealing effect can be achieved when the sealing agent is used in the high-humidity aluminized polyethylene film 4, the packaging liquid-tight effect can be guaranteed, the first layer A particle layer adopts 100% of linear medium density polyethylene resin, the effect of enhancing the heat sealing effect of the medium density metallocene polyethylene can be achieved, and the sealing agent has the function of auxiliary production after 15% of high-pressure low-density polyethylene resin is added due to the fact that the stiffness of the blown film formed by mixing the metallocene polyethylene and the linear polyethylene is not enough, so that a tube blank is blown into film bubbles stably, and the formability is improved.

The components of each layer structure in the high-humidity aluminum-plated polyethylene film 4 are mixed and then respectively added into three charging barrels of an extruder to respectively prepare a mixture of a first layer A particle layer, a mixture of a second layer B particle layer and a mixture of a third layer C particle layer, the mixtures in the three charging barrels are subjected to high-temperature melting through a high-temperature heating melting device of the extruder to form a tube blank, the tube blank is stretched and then extruded out from the center of a die head of the extruder and compressed with air, so that the tube blank is blown and expanded into film bubbles, meanwhile, the film bubbles are cooled and shaped through an air ring to prepare a film, the film prepared in the step S23 is sent into the aluminum plating machine, the film is subjected to double-corona vacuum evaporation, and the high-humidity aluminum-plated polyethylene film 4 is obtained through double-corona vacuum evaporation treatment. Compared with the common linear low density polyethylene, the high-humidity-resistance aluminized polyethylene film 4 prepared in the way has the advantages that the high-pressure low density content of the high-humidity-resistance aluminized polyethylene film 4 is high, and the high crystallinity can be achieved under the action of stress, so that a smaller free volume fraction is obtained, the glass transition temperature Tg of polymer molecules is increased, and the barrier property of the material is improvedAfter corona vapor aluminizing, the high-moisture-resistance aluminized polyethylene film 4 has enhanced barrier property, light shielding property and metallic luster effect, and the conventional 40 mu mPE water vapor transmission rate is 2.0-4.0 g/(m) ² 24 h), the water vapor transmission rate of the high-resistance wet-plating aluminum-plated polyethylene film 4 modified by the invention is 0.5-0.8 g/(m) ² 24 h), the barrier properties are greatly improved.

The high oxygen resistant polyethylene film 6 in the step S3) is formed by co-extruding a polyamide layer, a first high density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer with high oxygen resistant performance, a second bonding layer, a second high density polyethylene layer and a polyethylene layer, wherein the polyamide layer accounts for 25%, the first high density polyethylene layer accounts for 15%, the first bonding layer accounts for 5%, the ethylene-vinyl alcohol copolymer layer accounts for 10%, the second bonding layer accounts for 5%, the second high density polyethylene layer accounts for 15%, and the polyethylene layer accounts for 25%.

The polyamide layer of the high oxygen resistant polyethylene film 6 in the step S3) consists of 100 percent of polyamide; the first high density polyethylene layer consists of 70-75% linear low density polyethylene and 20-30% high pressure low density polyethylene; the first bonding layer is composed of 40-50% of bonding resin and 50-60% of linear low density polyethylene; the ethylene-vinyl alcohol copolymer layer is composed of 20-35% polymerized vinyl acetate and 74-76% polymerized ethylene; the second bonding layer is composed of 40-50% of bonding resin and 50-60% of linear low-density polyethylene; the second high density polyethylene layer consists of 70-75% linear low density polyethylene and 20-30% high pressure low density polyethylene; the polyethylene layer consists of 30-32% of metallocene, 30-32% of linear low density polyethylene, 30-34% of high pressure low density polyethylene, 0.5-2% of opening agent and 0.5-2% of slipping agent. Wherein, the high-oxygen-resistance polyethylene film 6 in the step S3) is prepared by the following processing steps:

step S31) weighing and mixing the components according to the corresponding percentage of each layer of components in the high-oxygen-resistance polyethylene film 6, and adding a mixture obtained by mixing the layers into seven charging barrels of an extruder;

step S32), mixing the mixture obtained in the step S1 into seven material cylinders of an extruder, heating and melting the mixture into a melt through a high-temperature heating and melting device of the extruder at the high-temperature melting temperature of 200-300 ℃, respectively preparing a polyamide layer, a first high-density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer with high oxygen resistance, a second bonding layer, a second high-density polyethylene layer and a polyethylene layer seven layer, co-extruding the mixture through the extruder, and then converging and heating the mixture in a T-shaped die after the mixture is circulated through a runner distributor;

step S33), the resin flowing out after the confluence and heating of the T-shaped die is coated with a film, the film is cooled by a cooling roller and is shaped to obtain the high-oxygen-resistance polyethylene film 6, and the density of the obtained high-oxygen-resistance polyethylene film 6 is 1.12g/cm ³ The oxygen transmission capacity of the high oxygen resistant polyethylene film 6 is less than or equal to 5.0cm ³ The friction coefficient of the high-oxygen-resistant polyethylene film 6 is 0.44 to 0.48 per square meter, 24h and 0.1MPa, the temperature required by heating the T-shaped die is 250 to 300 ℃, and the cooling temperature is 15 to 25 ℃;

and step S34) trimming the high-oxygen-resistance polyethylene film 6, and winding by a winding machine.

The thickness of the ethylene-vinyl alcohol copolymer layer is 7 mu m, and the melt flow index of the polymerized ethylene in the ethylene-vinyl alcohol copolymer layer is 6-12 g/10min.

The first bonding layer and the second bonding layer of the invention are both composed of 50% of bonding resin and 50% of linear low-density polyethylene, the bonding effect of bonding by adopting the bonding resin is good, the polyamide layer, the high-density polyethylene layer and the ethylene-vinyl alcohol copolymer layer can be well bonded together, and the density of polyamide in the polyamide layer is 1.15g/cm ³ The polyamide also has better tensile strength, puncture resistance and oxygen resistance, and the application of the film layers of the two high-density polyethylene layers ensures that the high-oxygen-resistance polyethylene film 6 has better oxygen resistance. In addition, the middle layer of the high oxygen resistant polyethylene film 6 mainly consists of an ethylene-vinyl alcohol copolymer layer, the ethylene-vinyl alcohol copolymer has excellent barrier property to gas and processability, can effectively prevent external water vapor and gas from permeating into package contents, has excellent heat sealing performance, strong pollution resistance and excellent heat sealing strength, and the ethylene-vinyl alcohol copolymer layerThe polymer has good affinity with polyamide, the ethylene-vinyl alcohol copolymer has high glass transition temperature and can adapt to forming processing, and the property can change the defect that a polyamide film layer is easy to deform when being heated. In addition, the high-oxygen-resistance polyethylene film 6 prepared by the invention has moderate friction coefficient, can not generate adhesion and skid when being cut off, and is very suitable for a high-speed packaging production line.

1. The invention is further illustrated below with reference to 4 specific examples provided by the invention:

1. in the second embodiment of the present invention, the polyethylene composite material of the present invention can be prepared by using the following film layers and components corresponding to the film layers, and the specific film layer structure is shown in the following table 1:

TABLE 1

2. In the third embodiment of the present invention, the polyethylene composite material of the present invention can be prepared by the following processing method, and the specific preparation process includes the following steps:

step S1) intaglio printing treatment: the prepared longitudinal stretching polyethylene film 1 with the thickness of 25 mu m is loaded on a first discharging shaft of a gravure printing machine, and the longitudinal stretching polyethylene film 1 is prepared by adopting the following processing steps:

step S11) preparing components of each layer by adopting the following components in percentage by weight in the longitudinally stretched polyethylene film 1, wherein 20% of medium-density metallocene and 80% of low-pressure high-density polyethylene resin are weighed to form a heat sealing layer; weighing 100% high-tensile metallocene in the middle layer; weighing 29% of medium-density metallocene, 70% of low-pressure high-density metallocene, 0.5% of opening agent and 0.5% of slipping agent in the corona layer, then mixing the components corresponding to each layer, adding the mixture obtained by mixing each layer into three charging barrels of a corresponding WH film blowing machine to respectively prepare the mixture of the heat-sealing layer, the mixture of the middle layer and the mixture of the corona layer, and plasticizing into a melt by high-temperature heating below the three charging barrels of the WH film blowing machine, wherein the high-temperature heating temperature is 250 ℃;

step S12) extruding the melt through a three-layer co-extrusion film blowing die head of a WH film blowing machine to obtain a molten film, wherein the extrusion speed is 550Kg/h, blowing up the molten film through the WH film blowing machine to form a film bubble, and then cooling;

step S13) flattening the cooled and formed film, feeding the film into MDO stretching equipment of a WH film blowing machine under the action of a rotary traction roller to carry out a stretching process, wherein the temperature during longitudinal stretching is 90 ℃, the stretching ratio of the film is 5, and carrying out heat setting at the temperature of 150 ℃ after stretching;

step S14), after corona treatment, trimming and rolling the stretched film to obtain a longitudinally stretched polyethylene film 1;

sending a longitudinal stretching polyethylene film 1 with the thickness of 25 micrometers to each printing color unit through a first feeding shaft of a printing machine, carrying out gravure printing by taking the longitudinal stretching polyethylene film 1 as a base material, printing a polyurethane ink layer 2 on the surface of the longitudinal stretching polyethylene film 1, controlling the viscosity of the ink to be 15 viscosity/Pa.s, setting the tension required by a first unwinding roller of the printing machine for unwinding the longitudinal stretching polyethylene film 1 to be 100N, and setting the winding tension after printing to be 120N;

step S2) first-pass composite processing: then the longitudinal stretching polyethylene film 1 with the thickness of 25 mu m printed in the step 1 is arranged at the end of a second discharging shaft, the tension required by the second discharging shaft for discharging the longitudinal stretching polyethylene film 1 with the thickness of 25 mu m is 120N, the prepared high-humidity-resistance aluminized polyethylene film 4 with the thickness of 40 mu m is arranged at the end of a third discharging shaft, the invention adopts the following processing steps to prepare the high-humidity-resistance aluminized polyethylene film 4,

step S21) configuring each layer of the high-humidity-resistance aluminum-plated polyethylene film 4 by adopting the following components in percentage by weight, wherein 100% of linear medium-density polyethylene resin is weighed in the first layer of the A particle layer, 80% of low-pressure high-density polyethylene resin and 20% of high-pressure low-density polyethylene resin are weighed in the second layer of the B particle layer; weighing 80% of medium-density metallocene polyethylene, 19% of high-pressure low-density polyethylene resin, 0.5% of opening agent and 0.5% of slipping agent in the third particle layer C, mixing the components corresponding to the layers, adding the mixture into three charging barrels of an extruder respectively after mixing, and preparing a mixture of the first particle layer A, a mixture of the second particle layer B and a mixture of the third particle layer C respectively;

step S22) carrying out high-temperature melting on the mixture in the three charging barrels in the step S21 through a high-temperature heating and melting device of an extruder to form a tube blank, wherein the temperature required by the high-temperature melting is 300 ℃;

step S24) feeding the film prepared in the step S23 into an aluminum plating machine, carrying out dicorotron vacuum evaporation on the film, and carrying out dicorotron vacuum evaporation treatment to obtain a high-humidity-resistance polyethylene film;

the method comprises the following steps that a third discharging shaft discharges a high-humidity-resistance aluminum-plated polyethylene film 4 with the tension of 140N, a 25-micron-thickness longitudinally-stretched polyethylene film 1 is fed into a first gluing system through a second discharging shaft end, a first glue applicator of the first gluing system coats a first layer of two-component polyurethane adhesive 3 on the inner surface of a processing surface of the 25-micron-thickness longitudinally-stretched polyethylene film 1, the coated 25-micron-thickness longitudinally-stretched polyethylene film 1 is fed into an oven to be dried, an organic solvent in the first layer of two-component polyurethane adhesive 3 is volatilized, the 25-micron-thickness longitudinally-stretched polyethylene film 1 enters three drying tunnels in the oven to be dried, the three drying tunnels are respectively at the temperatures of 50 ℃, 60 ℃ and 70 ℃, the longitudinally-stretched polyethylene film 1 dried by the three drying tunnels and the processing surface of the high-humidity-resistance aluminum-plated polyethylene film 4 are subjected to hot-press compounding to form a semi-finished composite film, the pressure required by the hot-press compounding guide roller is 0.35Mpa, the compounding speed is 90M/min, the first gravure roll with the 110-mesh screen, the coating amount of a coating roll is 75 g, and the half-finished composite film is wound by a coating roll with the tension of 200 g of 200N;

step S3) second-pass composite processing: loading the semi-finished composite film which is compounded for the first time into a fourth discharging shaft end, wherein the tension required by the fourth discharging shaft for discharging the semi-finished composite film is 160N, loading the prepared high-oxygen-resistant polyethylene film 6 with the thickness of 70 mu m into a fifth discharging shaft end, preparing the high-oxygen-resistant polyethylene film 6 by adopting the following steps,

step S31) the high-oxygen-resistant polyethylene film 6 adopts the following components by weight percent to configure each layer, 100 percent of polyamide is weighed on a polyamide layer, 72 percent of linear low-density polyethylene and 28 percent of high-pressure low-density polyethylene are weighed on a first high-density polyethylene layer, 40 percent of bonding resin and 60 percent of linear low-density polyethylene are weighed on a first bonding layer, 26 percent of polymerized vinyl acetate and 74 percent of polymerized ethylene are weighed on an ethylene-vinyl alcohol copolymer layer, 40 percent of bonding resin and 60 percent of linear low-density polyethylene are weighed on a second bonding layer, 72 percent of linear low-density polyethylene and 28 percent of high-pressure low-density polyethylene are weighed on a second high-density polyethylene layer, 37 percent of metallocene polyethylene, 30 percent of linear low-density polyethylene, 32 percent of high-pressure low-density polyethylene, 0.5 percent of opening agent and 0.5 percent of slipping agent are weighed on the polyethylene layer, the components corresponding to each layer are mixed, and the mixed materials obtained after mixing are added into seven charging barrels of an extruder;

step S32), mixing the mixture obtained in the step S1 into seven material cylinders of an extruder, heating and melting the mixture into a melt through a high-temperature heating and melting device of the extruder at the high-temperature melting temperature of 200-300 ℃, respectively preparing a polyamide layer, a first high-density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer, a second bonding layer, a second high-density polyethylene layer and a polyethylene layer seven layer, co-extruding the mixture through the extruder, and then converging and heating the mixture in a T-shaped die after the mixture is circulated through a runner distributor;

step S33), the resin flowing out after being converged and heated by the T-shaped die is sprayed and cooled by a cooling roller, and then the high-oxygen-resistance polyethylene film 6,T type die is obtained after being shaped, wherein the temperature required by heating is 250 ℃, the cooling temperature is 15 ℃, the temperature required by heating the T-shaped die is 250 ℃, and the cooling temperature is 15 ℃;

step S34) trimming the high-oxygen-resistance polyethylene film 6, and winding by a winding machine;

feeding the high-oxygen-resistance polyethylene film 6 by a fifth feeding shaft, wherein the tension required for feeding the high-oxygen-resistance polyethylene film 6 is 140N, feeding the semi-finished composite film into a second gluing system by a fourth feeding shaft, coating a second layer of two-component polyurethane adhesive 5 on the inner surface of a treated surface of a high-moisture-resistance aluminized polyethylene film 4 with the thickness of 40 mu M by a second gluing roller of the second gluing system, feeding the coated semi-finished composite film into an oven for drying, volatilizing an organic solvent in the second layer of two-component polyurethane adhesive 5, feeding the semi-finished composite film into three drying tunnels in the oven for drying, wherein the three drying tunnels have the temperatures of 50 ℃, 60 ℃ and 70 ℃, hot-pressing and compounding the semi-finished composite film discharged from the drying tunnels and the inner surface of the treated surface of the high-oxygen-resistance polyethylene film 6 to form a polyethylene composite material, the pressure required for the hot-pressing and compounding process of the polyethylene composite material is 0.35MPa, the compounding speed is 90M/min, the gluing mesh of the second gluing roller is a 110 mesh 75 mesh roller, the gluing amount is 3.2g, and the tension required for rolling of the polyethylene composite material is 240N/N.

3. In a fourth specific embodiment of the present invention, the polyethylene composite material of the present invention can be prepared by the following processing method, and the specific preparation process comprises the following steps:

step S11) preparing components of each layer by adopting the following components in percentage by weight in the longitudinally stretched polyethylene film 1, wherein 25% of medium-density metallocene and 75% of low-pressure high-density polyethylene resin are weighed to form a heat sealing layer; weighing 100% high-tensile metallocene in the middle layer; 27% of medium-density metallocene, 71% of low-pressure high-density metallocene, 1% of opening agent and 1% of slipping agent are weighed in the corona layer, then the components corresponding to each layer are mixed, the mixture obtained by mixing each layer is added into three charging barrels of a corresponding WH film blowing machine to respectively prepare the mixture of the heat sealing layer, the mixture of the middle layer and the mixture of the corona layer, and the mixture is plasticized into a melt by high-temperature heating below the three charging barrels of the WH film blowing machine, wherein the temperature of the high-temperature heating is 250 ℃;

step S13), flattening the cooled and formed film, feeding the film into MDO stretching equipment of a WH film blowing machine under the action of a rotary drawing roller to carry out a stretching process, wherein the temperature during longitudinal stretching is 90 ℃, the stretching ratio of the film is 5, and carrying out heat setting at 150 ℃ after stretching;

sending a longitudinal stretching polyethylene film 1 with the thickness of 25 microns to each printing color unit through a first discharging shaft of a printing machine, carrying out gravure printing by taking the longitudinal stretching polyethylene film 1 as a base material, printing a polyurethane ink layer 2 on the surface of the longitudinal stretching polyethylene film 1, controlling the viscosity of the ink to be 15 viscosity/Pa.s, setting the tension required by a first unwinding roller of the printing machine for unwinding the longitudinal stretching polyethylene film 1 to be 100N, and setting the winding tension after printing to be 120N;

step S2) first-pass composite processing: then loading the 25 mu m-thick longitudinally-stretched polyethylene film 1 printed in the step 1 into a second discharging shaft end, wherein the tension required by the second discharging shaft for discharging the 25 mu m-thick longitudinally-stretched polyethylene film 1 is 120N, loading the prepared 40 mu m-thick high-humidity aluminum-plated polyethylene film 4 into a third discharging shaft end, preparing the high-humidity aluminum-plated polyethylene film 4 by adopting the following processing steps,

step S21) preparing each layer of the high-humidity-resistance aluminized polyethylene film 4 by adopting the following components in percentage by weight, wherein 100% of linear medium density polyethylene resin is weighed in the first layer A particle layer, 82% of low-pressure high density polyethylene resin and 18% of high-pressure low density polyethylene resin are weighed in the second layer B particle layer; weighing 81% of medium-density metallocene polyethylene, 17% of high-pressure low-density polyethylene resin, 1% of an opening agent and 1% of a slipping agent in the third layer C particle layer, mixing the components corresponding to the layers, adding the mixture into three charging barrels of an extruder respectively after mixing, and preparing a mixture of the first layer A particle layer, a mixture of the second layer B particle layer and a mixture of the third layer C particle layer respectively;

step S22), carrying out high-temperature melting on the mixture in the three charging barrels in the step S21 through a high-temperature heating and melting device of an extruder to form a pipe blank, wherein the temperature required by the high-temperature melting is 300 ℃;

step S24) feeding the film prepared in the step S23 into an aluminum plating machine, carrying out double-corona vacuum evaporation on the film, and carrying out double-corona vacuum evaporation treatment to obtain a high-humidity-resistance polyethylene film 4;

the method comprises the following steps that a tension required by discharging a high-resistance wet aluminum-plated polyethylene film 4 through a third discharging shaft is 140N, a 25-micron-thick longitudinally-stretched polyethylene film 1 is fed into a first gluing system through a second discharging shaft end, a first glue coating roller of the first gluing system coats a first layer of two-component polyurethane adhesive 3 on the inner surface of a processing surface of the 25-micron-thick longitudinally-stretched polyethylene film 1, the coated 25-micron-thick longitudinally-stretched polyethylene film 1 enters an oven to be dried, organic solvent in the first layer of two-component polyurethane adhesive 3 is volatilized, the 25-micron-thick longitudinally-stretched polyethylene film 1 enters three drying tunnels in the oven to be dried, the three drying tunnels are respectively at 50 ℃, 60 ℃ and 70 ℃, the longitudinally-stretched polyethylene film dried by the three drying tunnels is subjected to hot-press compounding with the processing surface of the high-resistance wet aluminum-plated polyethylene film 4 to form a semi-finished composite film, the pressure required by the hot-press compounding guide roller is 0.35MPa, the compounding speed is 90M/min, the first roll is 110 meshes, the gravure roll, the glue coating amount of the glue coating roller is 3.5g to 3-200 g, and the semi-finished composite film is coated with the glue coating tension required by the glue amount of N;

step S3) second-pass composite processing: loading the semi-finished composite film which is compounded for the first time into a fourth discharging shaft end, wherein the tension required for discharging the semi-finished composite film by the fourth discharging shaft end is 160N, and loading the prepared high-oxygen-resistant polyethylene film 6 with the thickness of 70 micrometers into a fifth discharging shaft end, the invention adopts the following steps to prepare the high-oxygen-resistant polyethylene film 6, S31) the high-oxygen-resistant polyethylene film 6 adopts the following components in percentage by weight to configure each layer, 100% of polyamide is weighed by a polyamide layer, 73% of linear low-density polyethylene and 27% of high-pressure low-density polyethylene are weighed by a first high-density polyethylene layer, 45% of adhesive resin and 55% of linear low-density polyethylene are weighed by a first adhesive layer, 25% of polymerized vinyl acetate and 75% of polymerized ethylene are weighed by an ethylene-vinyl alcohol copolymer layer, 45% of adhesive resin and 55% of linear low-density polyethylene are weighed by a second adhesive layer, 73% of linear low-density polyethylene and 27% of high-pressure low-density polyethylene are weighed by a second high-density polyethylene layer, 37% of metallocene polyethylene, 31% of linear low-density polyethylene, 31% of low-density polyethylene and 1% of opening agent are weighed by a mixing machine, and then extruding seven mixed materials into a charging barrel;

step S32), mixing the mixture obtained in the step S1 into seven material cylinders of an extruder, heating and melting the mixture into a melt through a high-temperature heating and melting device of the extruder at the high-temperature melting temperature of 200 ℃, respectively preparing a polyamide layer, a first high-density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer, a second bonding layer, a second high-density polyethylene layer and a polyethylene layer seven layer, co-extruding the polyamide layer, the first high-density polyethylene layer, the first bonding layer, the ethylene-vinyl alcohol copolymer layer, the second bonding layer, the second high-density polyethylene layer and the polyethylene layer, then converging and heating the mixture in a T-shaped die after the mixture is circulated through a runner distributor;

step S33), the resin flowing out after the T-shaped die heads are converged and heated is subjected to film spraying, and the high-oxygen-resistance polyethylene film 6,T die heads are obtained by cooling and shaping through a cooling roller, wherein the heating temperature is 250 ℃ and the cooling temperature is 20 ℃;

4. In a fifth embodiment of the present invention, the polyethylene composite material of the present invention can be prepared by the following processing method, and the specific preparation process includes the following steps:

step S1) intaglio printing treatment: the prepared longitudinal stretching polyethylene film 1 with the thickness of 25 mu m is loaded on a first discharging shaft of a gravure printing machine, and the longitudinal stretching polyethylene film 1 is prepared by the following processing steps:

step S11) preparing components of each layer by adopting the following components in percentage by weight in the longitudinally stretched polyethylene film 1, wherein 33% of medium-density metallocene and 67% of low-pressure high-density polyethylene resin are weighed to form a heat sealing layer; weighing 100% high-tensile metallocene in the middle layer; weighing 33% of medium-density metallocene, 63% of low-pressure high-density metallocene, 2% of a shedding agent and 2% of a slipping agent in the corona layer, then mixing the weighed components corresponding to each layer, adding a mixture obtained by mixing the layers into three charging barrels of a corresponding WH film blowing machine to respectively prepare a mixture of the heat-sealing layer, a mixture of the middle layer and a mixture of the corona layer, and plasticizing into a melt by high-temperature heating below the three charging barrels of the WH film blowing machine, wherein the high-temperature heating temperature is 250 ℃;

step S12) extruding the melt through a three-layer co-extrusion film blowing die head of a WH film blowing machine to obtain a molten film, wherein the extrusion speed is 550Kg/h, performing inflation on the molten film through the WH film blowing machine to form a film bubble, and then cooling;

step S21) configuring each layer of the high-humidity-resistance aluminum-plated polyethylene film 4 by adopting the following components in percentage by weight, wherein 100% of linear medium-density polyethylene resin is weighed in the first layer of the A particle layer, 85% of low-pressure high-density polyethylene resin and 15% of high-pressure low-density polyethylene resin are weighed in the second layer of the B particle layer; weighing 81% of medium-density metallocene polyethylene, 15% of high-pressure low-density polyethylene resin, 2% of opening agent and 2% of slipping agent in the third particle layer C, mixing the components corresponding to the layers, adding the mixture into three charging barrels of an extruder respectively after mixing, and preparing a mixture of the first particle layer A, a mixture of the second particle layer B and a mixture of the third particle layer C respectively;

step S24) feeding the film prepared in the step S23 into an aluminum plating machine, carrying out double-corona vacuum evaporation on the film, and carrying out double-corona vacuum evaporation treatment to obtain a high-humidity-resistance polyethylene film;

the tension required by discharging the high-humidity aluminum-plated polyethylene film 4 by a third discharging shaft is 140N, the 25-micron-thickness longitudinally-stretched polyethylene film 1 is fed into a first gluing system through a second discharging shaft end, a first glue applicator of the first gluing system coats a first layer of two-component polyurethane adhesive 3 on the inner surface of a processing surface of the 25-micron-thickness longitudinally-stretched polyethylene film 1, the coated 25-micron-thickness longitudinally-stretched polyethylene film 1 enters an oven for drying, organic solvent in the first layer of two-component polyurethane adhesive 3 is volatilized, the 25-micron-thickness longitudinally-stretched polyethylene film 1 enters three drying tunnels in the oven for drying, the three drying tunnels are respectively at the temperature of 50 ℃, 60 ℃ and 70 ℃, the longitudinally-stretched polyethylene film 1 dried by the three drying tunnels is hot-pressed and compounded with the processing surface of the high-humidity aluminum-plated film 4 to form a semi-finished composite film, the pressure required by the hot-pressing composite hot-pressing process is 0.35MPa, the composite speed is 90M/min, the first glue applicator roll is 110 meshes, the glue applicator roll is used for rolling, the coating amount of a gravure-coating roll is 3.5g, and the semi-coating tension required by the semi-coating weight of the polyethylene film is 200.5 g, and the semi-finished composite film is 200.5 g of the coating roll;

step S31) the high-oxygen-resistant polyethylene film 6 adopts the following components by weight percent to configure each layer, 100 percent of polyamide is weighed on a polyamide layer, 75 percent of linear low-density polyethylene and 25 percent of high-pressure low-density polyethylene are weighed on a first high-density polyethylene layer, 50 percent of bonding resin and 50 percent of linear low-density polyethylene are weighed on a first bonding layer, 24 percent of polymerized vinyl acetate and 76 percent of polymerized ethylene are weighed on an ethylene-vinyl alcohol copolymer layer, 50 percent of bonding resin and 50 percent of linear low-density polyethylene are weighed on a second bonding layer, 75 percent of linear low-density polyethylene and 25 percent of high-pressure low-density polyethylene are weighed on a second high-density polyethylene layer, 32 percent of metallocene polyethylene, 32 percent of linear low-density polyethylene, 32 percent of high-pressure low-density polyethylene, 2 percent of opening agent and 2 percent of slipping agent are weighed on the polyethylene layer, the components corresponding to each layer are mixed, and the mixed materials obtained after mixing are added into seven charging barrels of an extruder;

step S33), the resin flowing out after the T-shaped die heads are converged and heated is subjected to film spraying, and the high-oxygen-resistance polyethylene film 6,T die heads are obtained by cooling and shaping through a cooling roller, wherein the heating temperature is 250 ℃ and the cooling temperature is 15 ℃;

feeding the high-oxygen-resistance polyethylene film 6 by a fifth feeding shaft with the tension of 140N, feeding the semi-finished composite film into a second gluing system by a fourth feeding shaft, coating a second layer of two-component polyurethane adhesive 5 on the inner surface of a treated surface of a high-humidity aluminum-plated polyethylene film 4 with the thickness of 40 mu M by a second glue coating roller of the second gluing system, feeding the coated semi-finished composite film into an oven for drying, volatilizing an organic solvent in the second layer of two-component polyurethane adhesive 5, feeding the semi-finished composite film into three drying tunnels in the oven for drying, performing hot-pressing compounding on the semi-finished composite film discharged from the drying tunnels and the inner surface of the treated surface of the high-oxygen-resistance polyethylene film 6 at the temperatures of 50 ℃, 60 ℃ and 70 ℃ to form the polyethylene composite material, wherein the pressure required by the hot-pressing compounding guide roller of the polyethylene composite material is 0.35MPa, the compounding speed is 90M/min, the gravure screen of the second glue coating roller is a 110 x 75 screen roller, the coating amount is 3.2g, and the tension required by rolling of the polyethylene composite material is 240N.

2. The polyethylene composite materials prepared by the methods of the third, fourth and fifth embodiments are cut out for testing the barrier property and the heat sealing property, and the test conditions are as follows:

1. the test method comprises the following steps: testing the moisture permeability of the barrier property of the polyethylene composite material according to a method specified in the national standard GB/T26253, wherein the testing conditions are as follows: the testing temperature is 38 ℃, the relative humidity is 90%, and the heat sealing surface faces to the side with low humidity during testing;

testing the oxygen transmission rate of the barrier property of the polyethylene composite material according to the method of the national standard GB/T1038-1988, wherein in the testing process, the non-heat sealing surface faces to the oxygen side;

carrying out heat sealing on the polyethylene composite materials prepared in the third, fourth and fifth examples under the condition that the sealing pressure is 200kpa according to a method specified by national standard QB/T2358, wherein the cut width of the polyethylene composite materials in the third, fourth and fifth examples is 15mm, the cut length of the polyethylene composite materials in the third, fourth and fifth examples is 100mm, drawing a change curve of the heat sealing strength of the polyethylene composite materials along with the heat sealing time, and recording the optimal heat sealing temperature and heat sealing strength;

2. and (3) testing results: see table 2 below:

TABLE 2

3. And (4) testing conclusion: as shown in table 2, the polyethylene composite material prepared by the processing method of the present invention has not only excellent water vapor barrier property and oxygen barrier property, but also high heat sealing property, and the water vapor barrier property and the oxygen barrier property in example five are more significant.

3. The polyethylene composite materials prepared by the methods of the third, fourth and fifth embodiments are cut out for mechanical property tests, and the test conditions are as follows:

1. the test method comprises the following steps: testing the breaking force and the breaking elongation of the polyethylene composite material according to the method of the national standard GB/T1040.3;

2. and (3) testing results: see table 3 below:

TABLE 3

3. And (4) test conclusion: as shown in table 3, the polyethylene composite material prepared by the processing method of the present invention has excellent mechanical properties, and the water vapor barrier property and the oxygen barrier property in the polyethylene composite material of example five are more significant.

4. And (3) performing material identification on each layer of the polyethylene composite material prepared in the second embodiment:

each layer of the prepared single polyethylene environment-friendly composite material is peeled off, the glue among the polyethylene composite material layers is wiped by using a solvent, and then the material quality is identified by using an infrared spectrum identification instrument, and the detection conditions of the polyethylene composite material adopting a longitudinally stretched polyethylene film 1, a high-humidity aluminum-plated polyethylene film 4 and a high-oxygen-resistance polyethylene film 6 are shown in figures 3-5. And it can be obtained from the spectrograms of the infrared spectrometers in fig. 3-5 that the material structures of the layers of the polyethylene composite material are single polyethylene environment-friendly composite material.

From the above embodiments and test results, it can be seen that the polyethylene composite material prepared by the processing method of the present invention is prepared by stacking and compounding the longitudinal stretched polyethylene film 1, the high-moisture-resistant aluminum-plated polyethylene film 4 and the high-oxygen-resistant polyethylene film 6 in three layers, the longitudinal stretched polyethylene film 1 is used as the outer layer, the high-moisture-resistant aluminum-plated polyethylene film 4 is used as the intermediate layer, the high-oxygen-resistant polyethylene film 6 is used as the inner layer, and each layer of the film is designed by a unique formula, so that the polyethylene composite material is easier to process during preparation, and the barrier property and the heat sealing property of the polyethylene composite material are improved, and the mechanical property is also improved.

The present invention has been described in detail, and it should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Claims

1. A processing method for preparing a single polyethylene composite material, characterized in that: the processing method comprises the following steps of:

step S2) first-pass composite processing: loading the 25 mu M-thick longitudinally-stretched polyethylene film printed in the step 1 into a second discharging shaft end, wherein the tension required by the second discharging shaft for discharging the 25 mu M-thick longitudinally-stretched polyethylene film is 120N, loading the prepared 40 mu M-thick high-resistance wet-plating aluminum-plated polyethylene film into a third discharging shaft end, wherein the tension required by the third discharging shaft for discharging the 40 mu M-thick high-resistance wet-plating aluminum-plated polyethylene film is 140N, feeding the 25 mu M-thick longitudinally-stretched polyethylene film into a first gluing system through the second discharging shaft end, coating a first layer of bicomponent polyurethane adhesive on the inner surface of the 25 mu M-thick longitudinally-stretched polyethylene film by a first gluing roller of the first gluing system, the coated 25-micron-thick longitudinally-stretched polyethylene film enters an oven for drying, organic solvent in a first layer of double-component polyurethane adhesive is volatilized, the 25-micron-thick longitudinally-stretched polyethylene film enters three drying channels in the oven for drying, the temperatures of the three drying channels are respectively 50 ℃, 60 ℃ and 70 ℃, the longitudinally-stretched polyethylene film dried by the three drying channels and the processing surface of the high-humidity aluminum-plated polyethylene film are subjected to hot-pressing compounding to form a semi-finished product composite film, the pressure required by the hot-pressing process of a hot-pressing compounding guide roller is 0.35Mpa, the compounding speed is 90M/min, the gluing mesh of the first glue coating roller is a 110 x 75 gravure mesh roller, the gluing amount is 3.2-3.5 g/square meter, and the tension required by rolling of the semi-finished product composite film is 200N;

step S3) second-pass composite processing: loading the first-time compounded semi-finished product composite film into a fourth discharging shaft end, wherein the tension required by the fourth discharging shaft for discharging the semi-finished product composite film is 160N, loading a prepared high-oxygen-resistance polyethylene film with the thickness of 70 micrometers into a fifth discharging shaft end, wherein the tension required by the fifth discharging shaft for discharging the high-oxygen-resistance polyethylene film with the thickness of 70 micrometers is 140N, sending the semi-finished product composite film into a second gluing system through the fourth discharging shaft, coating a second layer of two-component polyurethane adhesive on the inner surface of a high-humidity aluminum-plated polyethylene film treatment surface with the thickness of 40 micrometers by a second gluing roller of the second gluing system, drying the coated semi-finished product composite film in an oven, volatilizing an organic solvent in the second layer of two-component polyurethane adhesive, drying the semi-finished product composite film in three drying lanes, wherein the temperatures of the three drying lanes are respectively 50 ℃, 60 ℃,70 ℃, hot-pressing and compounding the semi-finished product composite film and the inner surface of the high-oxygen-plated polyethylene film to form a polyethylene composite material, and the hot-pressing compounding guide roller with the tension of the hot-pressing and the hot-pressing compounding roller with the tension of the weight of 0.35MPa and the second mesh 3-3.3-mesh.

2. The process for the preparation of a unitary polyethylene composite according to claim 1, characterized in that: the type of the first layer of two-component polyurethane adhesive and the second layer of two-component polyurethane adhesive used in the steps S2) and S3) is the type of 'XH-66F/XH-K75', and the proportion of the two-component polyurethane adhesive is as follows: host XH-66F: curing agent XH-K75: ethyl acetate solvent = 20.

3. The process for the preparation of a unitary polyethylene composite according to claim 1, characterized in that: the longitudinally stretched polyethylene film in the step S1) is prepared from a heat sealing layer, a middle layer and a corona layer, wherein the heat sealing layer accounts for 30%, the middle layer accounts for 40%, and the corona layer accounts for 30%; the heat sealing layer consists of 5-33% of medium-density metallocene and 5-80% of low-pressure high-density polyethylene resin; the intermediate layer is composed of 100% high tensile metallocene; the corona layer is composed of 5-33% of medium-density metallocene, 10-75% of low-pressure high-density metallocene, 0.5-2% of an opening agent and 0.5-2% of a slipping agent.

4. The process for the preparation of a unitary polyethylene composite according to claim 3, characterized in that: the longitudinally stretched polyethylene film in the step S1) is prepared by the following processing steps:

5. The process for the preparation of a unitary polyethylene composite according to claim 1, characterized in that: the high-humidity-resistance aluminized polyethylene film in the step S2) is prepared by high-temperature fusion of a first layer A particle layer, a second layer B particle layer and a third layer C particle layer, wherein the proportion of the first layer A particle layer is 30%, and the proportion of the second layer B particle layer is 40%; the proportion of the third layer of particles C is 30%, wherein the first layer of particles A is composed of 100% of linear medium density polyethylene resin; the second layer of particles B consists of 80 to 85 percent of low-pressure high-density polyethylene resin and 10 to 25 percent of high-pressure low-density polyethylene resin; the third layer of particle C consists of 80-81% of medium density metallocene polyethylene, 14-25% of high pressure low density polyethylene resin, 0.5-2% of opening agent and 0.5-2% of slipping agent.

6. The process for the preparation of a unitary polyethylene composite according to claim 5, characterized in that: the high-humidity-resistance aluminized polyethylene film in the step S2) is prepared by the following processing steps:

7. The process for the preparation of a unitary polyethylene composite according to claim 6, characterized in that: the water vapor transmission rate of the high-resistance wet-plating aluminum polyethylene film prepared by the steps S21) to S24) is 0.5-0.8 g/(m) ² ·24h)。

8. The process for the preparation of a unitary polyethylene composite according to claim 1, characterized in that: the high oxygen resistant polyethylene film in the step S3) is formed by co-extruding seven layers of a polyamide layer, a first high density polyethylene layer, a first bonding layer, an ethylene-vinyl alcohol copolymer layer, a second bonding layer, a second high density polyethylene layer and a polyethylene layer, wherein the polyamide layer accounts for 25%, the first high density polyethylene layer accounts for 15%, the first bonding layer accounts for 5%, the ethylene-vinyl alcohol copolymer layer accounts for 10%, the second bonding layer accounts for 5%, the second high density polyethylene layer accounts for 15% and the polyethylene layer accounts for 25%.

9. The process for the preparation of a unitary polyethylene composite according to claim 8, characterized in that: the polyamide layer of the high-oxygen-resistance polyethylene film in the step S3) consists of 100% of polyamide; the first high density polyethylene layer consists of 70-75% of linear low density polyethylene and 20-30% of high pressure low density polyethylene; the first bonding layer is composed of 40-50% of bonding resin and 50-60% of linear low density polyethylene; the ethylene-vinyl alcohol copolymer layer is composed of 20-35% polymerized vinyl acetate and 74-76% polymerized ethylene; the second bonding layer is composed of 40-50% of bonding resin and 50-60% of linear low density polyethylene; said second high density polyethylene layer consisting of 70-75% linear low density polyethylene and 20-30% high pressure low density polyethylene; the polyethylene layer consists of 30-40% of metallocene polyethylene, 30-32% of linear low density polyethylene, 30-34% of high pressure low density polyethylene, 0.5-2% of an opening agent and 0.5-2% of a slipping agent.

10. The process for the preparation of a unitary polyethylene composite according to claim 9, characterized in that: the high-oxygen-resistance polyethylene film in the step S3) is prepared by the following processing steps:

step S33), the resin flowing out after being converged and heated by the T-shaped die head is coated with a film, the film is cooled by a cooling roller and shaped to obtain the high-oxygen-resistance polyethylene film, and the density of the obtained high-oxygen-resistance polyethylene film is 1.12g/cm ³ The oxygen transmission capacity of the high oxygen resistant polyethylene film is less than or equal to 5.0cm ³ Per square meter (24 h.0.1 MPa), the friction coefficient of the high-oxygen-resistant polyethylene film is 0.44-0.48, the temperature required by heating the T-shaped die is 250-300 ℃, and the cooling temperature is 15-25 ℃;

and step S34) cutting edges of the high-oxygen-resistance polyethylene film, and winding the high-oxygen-resistance polyethylene film by a winding machine.