CN115302886B

CN115302886B - Packaging material, preparation method thereof and packaging container

Info

Publication number: CN115302886B
Application number: CN202211244955.2A
Authority: CN
Inventors: 孙忠杰; 宋夫前; 李宜彬; 边浩亮
Original assignee: Ningbo Times Aluminium Foil Technology Corp ltd
Current assignee: Ningbo Times Aluminium Foil Technology Corp ltd
Priority date: 2022-10-12
Filing date: 2022-10-12
Publication date: 2022-12-16
Anticipated expiration: 2042-10-12
Also published as: CN115302886A

Abstract

The invention discloses a packaging material, a preparation method thereof and a packaging container, wherein the preparation method of the packaging material comprises the following steps: coating a first adhesive on the first surface of the aluminum foil layer, and laying a first fiber layer; coating the outer polymer layer in a molten state on the first fiber layer and cooling; coating a second adhesive on the second surface of the aluminum foil layer, and laying a second fiber layer; and coating the polymer inner layer in a molten state on the second fiber layer and cooling to obtain the packaging material. The invention can facilitate the separation of the aluminum foil layer and the outer layer or the inner layer thereon. Therefore, the packaging material of the present invention is convenient for recycling.

Description

Packaging material, preparation method thereof and packaging container

Technical Field

The invention belongs to the technical field of packaging elements, and particularly relates to a composite packaging material which is applied with a coating material for realizing a special packaging purpose (a purpose of convenient recycling).

Background

The aluminum foil package is a common element in food packaging, medicine packaging, electronic component, photoelectric product and other electronic product packaging, and has the characteristics of light resistance, constant temperature, no toxicity, low cost and the like. The aluminum foil package is mostly matched with films such as paper, plastic films and the like to manufacture composite material package elements. In order to improve the quality and performance of aluminum foil packaging, those skilled in the art have conducted many studies and improvements thereon.

For example, chinese patent No. CN101108677B discloses an aluminum foil for food and drug packaging, which has an adhesive layer on one side of an aluminum foil layer and a two-component polymer primer layer on the other side. The aluminum foil material can be used for direct UV flexographic printing.

For another example, chinese patent application publication No. CN107892090a discloses an aluminum foil-based composite packaging material, which includes a heat-sealing layer, a first graphene layer, an aluminum foil layer, a second graphene layer, a first adhesive layer, a kraft paper layer, a second adhesive layer, a film layer, and a printing layer. The composite packaging material has good tensile strength and sealing performance, and is suitable for food packaging.

As can be seen from the above examples, the mechanical strength, toughness and sealing performance are the directions of the present skilled person to focus on the improvement. However, in addition to the above-mentioned direction of improvement, it is also important and not negligible how to increase the degree of recyclability of the aluminium foil packaging material.

In particular, the cost of aluminum foil is relatively high and it is necessary to recycle it. However, the inner and outer surfaces of the aluminum foil wrapper are typically covered with polymer film layers. The technical difficulty faced by the related art at present is how to realize mutual stripping of the polymer film layer and the aluminum foil during recycling.

Therefore, how to provide a packaging material convenient for recycling aluminum foil is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The invention aims to provide a packaging material, a preparation method thereof and a packaging container, and provides the packaging material convenient for recycling aluminum foil. In order to solve the above-mentioned technical problems, the present invention has been accomplished as described above.

The invention provides a preparation method of a packaging material, which comprises the following steps:

s100, coating a first adhesive on the first surface of the aluminum foil layer, and laying a first fiber layer;

s200, coating the outer polymer layer in a molten state on the first fiber layer and cooling;

s300, coating a second adhesive on the second surface of the aluminum foil layer, and laying a second fiber layer;

s400, coating the molten polymer inner layer on a second fiber layer and cooling to obtain a packaging material;

wherein the first fiber layer and the second fiber layer are respectively prepared by the following steps:

s501, preparing polyacrylamide: polyparaphenylene terephthalamide = (30-40): 100, mixing polyacrylamide and poly-p-phenylene terephthamide, and dissolving in a dimethyl acetamide solvent to prepare a spinning solution with the concentration of 10-12 wt%;

s502, feeding the spinning solution into a capillary injection needle and pushing the capillary injection needle to inject the spinning solution to a rolling and grounded collecting roller, wherein a 12-14 kV direct-current electric field is applied between the capillary injection needle and the collecting roller which are spaced from each other;

s503, taking out and spreading the collected matter in the collecting roller to obtain a fiber layer.

Further, the first fiber layer and the second fiber layer are respectively disordered flocculent fibers with the diameter of 10-20 microns.

Further, in S502, the advancing speed of the capillary injection needle is 2 ml/h to 4 ml/h; and or the distance between the capillary injection needle and the collecting roller is 16 cm-18 cm; and/or the rotating speed of the collecting roller is 300-400 rpm; and/or the length of the cylinder body of the collecting roller is 240 mm-260 mm; and or the diameter of the collecting roller is 80 mm-100 mm.

Further, S100 includes:

s101, mixing aminopropyltrimethoxysilane, polyoxyethylene polyoxypropylene pentaerythritol ether, 2-amino-2-methyl-1-propanol, phenolic resin, acrylic resin and pinene resin to obtain a first mixture;

s102, mixing and extruding the first mixture at the temperature of 110-120 ℃ to obtain a first adhesive;

s103, coating a first adhesive on the first surface of the aluminum foil layer, and paving a first fiber layer on the first surface.

Further, in S101, the molar ratio of aminopropyltrimethoxysilane: polyoxyethylene polyoxypropylene pentaerythritol ether: 2-amino-2-methyl-1-propanol: phenolic resin: acrylic resin: pinene resin = (2-4): (2-4): (2-4): (10-20): (20-30): 100 mass ratio, aminopropyltrimethoxysilane, polyoxyethylene polyoxypropylene pentaerythritol ether, 2-amino-2-methyl-1-propanol, phenolic resin, acrylic resin and pinene resin are mixed.

Further, S200 includes:

s201, mixing and extruding calcium propionate, methyl p-hydroxybenzoate, vinyl pyrrolidone-vinyl acetate copolymer, polyethylene resin and polypropylene resin at the temperature of 180-200 ℃ to obtain a polymer outer layer in a molten state;

and S202, coating the polymer outer layer in the molten state on the first fiber layer and naturally cooling to room temperature.

Further, in S201, the ratio of calcium propionate: methyl paraben: vinylpyrrolidone-vinyl acetate copolymer: polyethylene resin: polypropylene resin = (2-4): (2-4): (20-30): (70-80): 100 mass ratio, calcium propionate, methyl parahydroxybenzoate, vinyl pyrrolidone-vinyl acetate copolymer, polyethylene resin and polypropylene resin were kneaded and extruded.

Further, S400 includes:

s401, mixing and extruding talcum powder, beeswax, polyvinyl alcohol resin and polylactic resin at 220-240 ℃ to obtain a molten polymer inner layer;

s402, coating the molten polymer inner layer on the second fiber layer and cooling to obtain the packaging material.

Further, in step S401, the raw material ratio is talc: beeswax: polyvinyl alcohol resin: polylactic acid resin = (4-6): (4-6): (70-80): 100.

the invention also provides a packaging material, which is obtained by adopting the preparation method of any one of the technical schemes.

The packaging material is obtained by the preparation method according to any one of the above technical schemes, so that the packaging material has all the beneficial effects of the preparation method according to any one of the above technical schemes, and the details are not repeated herein.

The invention also provides a packaging container which is prepared from the packaging material of any one of the technical schemes.

The invention provides a packaging container which is prepared from the packaging material of any one of the technical schemes.

The packaging container is prepared from the packaging material of any technical scheme, so that the packaging container has all the beneficial effects of the packaging material of any technical scheme, and the details are not repeated.

The invention has the following beneficial effects: the invention provides a preparation method of a packaging material, which comprises the following steps of firstly, bonding a polymer outer layer and an aluminum foil layer with each other through a first adhesive, and arranging a fiber layer between the polymer outer layer and the aluminum foil layer. Furthermore, the preparation method bonds the polymer inner layer and the aluminum foil layer with each other through a second adhesive, and a fiber layer is arranged between the polymer inner layer and the aluminum foil layer. In other words, the polymer layer is respectively applied on the front surface and the back surface of the aluminum foil layer, and the fiber layer is laid between the polymer layer and the aluminum foil. One of the improvements of the invention lies in the provision of the fibrous layers. The fiber layer has the functions of: the polymer layer and the aluminum foil can be peeled off from each other conveniently, so that the aluminum foil layer is recycled conveniently. In addition, the arrangement of the fiber layer does not affect the stability and durability of the aluminum foil package. The aluminum foil package containing the fiber layer does not have the problem of peeling or delamination under a high-temperature or high-humidity use environment.

Drawings

The advantages of the foregoing aspects of the invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural view of an electrospinning apparatus used in the production of a fiber layer according to the present invention;

FIG. 2 is a microscopic electron micrograph of a fibrous layer that has been subjected to hot water immersion;

description of reference numerals:

101: a capillary injection needle; 102: a needle cylinder; 103: a needle head; 104: a propeller; 105: jetting a thin flow; 106: and collecting the roller.

Detailed Description

The following examples, which are illustrative only and not to be construed as limiting the invention, will now be described in detail. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

The embodiment of the invention provides a preparation method of a packaging material, which comprises the following steps:

and S400, coating the molten polymer inner layer on the second fiber layer and cooling to obtain the packaging material.

In the above embodiment, the aluminum foil-based packaging material is mainly used for packaging foods, drinks, and medicines. The packaging material includes an aluminum foil layer, and polymer layers (i.e., a polymer outer layer and a polymer inner layer) covering both upper and lower surfaces of the aluminum foil layer. Wherein, the aluminum foil layer has soft texture, good ductility and better glossiness. However, the aluminum foil itself is easily oxidized to become dark, and therefore, the embodiment of the present invention improves the durability and barrier property of the packaging material in the form of aluminum-plastic composite by applying the polymer layer on the surface of the aluminum foil layer.

The aluminum foil layer, adhesive, and polymer layer used in embodiments of the present invention are all commercially available. The aluminum foil layer is a layered material formed by directly rolling metal aluminum into a sheet, and the polymer outer layer and the polymer inner layer can be respectively prepared from high molecular polymers such as polyvinyl chloride, polyethylene, polypropylene, polystyrene and the like. The adhesive is specifically a synthetic resin adhesive, which may be specifically an epoxy adhesive, or a phenolic adhesive, or a polyurethane adhesive, or an allyl adhesive.

The first adhesive is used for adhering the first fiber layer to the first surface of the aluminum foil layer, and the second adhesive is used for adhering the second fiber layer to the second surface of the aluminum foil layer. It will be appreciated that the first and second surfaces are opposite side surfaces of the aluminium foil layer. The first adhesive and the second adhesive may be the same type of adhesive or different types of adhesives.

Both the outer polymer layer and the inner polymer layer are applied in a coating manner on the aluminium foil covered with the fibre layer. The coating can be manual coating or mechanical coating. The thickness of the coating can be selected by the person skilled in the art according to the actual need. It is understood that the polymer outer layer and the polymer inner layer are respectively in a flowing state or a semi-solidified state (for example, a molten state), and after the polymer outer layer and the polymer inner layer are coated and are left to stand and cool, the polymer layer is solidified into a film to cover the surfaces of the aluminum foil layer and the fiber layer.

The first fiber layer and the second fiber layer have the following functions: the polymer layer and the aluminum foil can be peeled off from each other conveniently, so that the aluminum foil layer can be recycled conveniently. Wherein the first fiber layer and the second fiber layer are respectively prepared by the following steps:

Illustratively, assuming 30 grams of polyacrylamide and 100 grams of poly-p-phenylene terephthalamide are mixed, 1170 grams of dimethylacetamide solvent is added, thereby obtaining a total weight of 1300 grams of spinning dope, the total weight of polyacrylamide and poly-p-phenylene terephthalamide (130 grams) being 10% of the total weight of the spinning dope, i.e.: the mass concentration of the spinning solution is 10 wt%.

The fiber layer that this application embodiment prepared is specifically aramid fiber layer. The aramid fiber has the advantages of flame retardance, heat resistance and strong toughness, and has a wide application prospect in the field of textiles. Poly-p-phenylene terephthamide (PPTA) is the main raw material for preparing aramid fiber. In the embodiment of the application, a certain proportion of polyacrylamide and poly-p-phenylene terephthalamide are mixed, and dimethylacetamide is added as a solvent, so that the spinning solution with poly-p-phenylene terephthalamide as a main material is prepared. Further, the spinning solution is spun into an aramid fiber containing polyacrylamide in the electrospinning step of step S502.

Polyacrylamide, poly (p-phenylene terephthalamide), and dimethylacetamide are commercially available. Illustratively, in order to improve the solubility of poly (p-phenylene terephthalamide) in a solvent, the poly (p-phenylene terephthalamide) required in step S501 may be prepared by the following method in the examples of the present application:

firstly, according to the following steps of 15:15:10:10, sequentially weighing p-phenylenediamine, o-chloro-p-phenylenediamine, 3,4' -diaminodiphenyl ether and 2,5-diaminobenzene sulfonic acid, and uniformly mixing the raw materials to obtain a monomer;

furthermore, according to 45:55, sequentially weighing N, N-dimethylformamide and N-methylpyrrolidone, and uniformly mixing the raw materials at the temperature of 85 ℃ to obtain a solvent;

subsequently, the following monomers: solvent = (20-30): 100, stirring the mixture at room temperature until the mixture is dissolved, slowly dropwise adding terephthaloyl chloride with the addition amount being 1.5 times of the monomer amount after the mixture is dissolved, stirring the mixture for reaction, and performing alkali washing, water washing and drying on the product after the reaction is finished to obtain the poly (p-phenylene terephthalamide).

The steps adopt monomers containing chlorine and ammonia as raw materials for synthesizing the poly-p-phenylene terephthalamide, so that the free volume between monomer molecules can be increased, and the hydrogen bonding effect between molecules is weakened. Therefore, the poly-p-phenylene terephthalamide obtained by polymerizing the monomers has relatively high solubility and flow property, and is more suitable for the injection process of electrostatic spinning.

The principle of electrostatic spinning is as follows: the electrostatic charge is applied to the droplets of polymer dope which, under the action of an electric field, is able to overcome its surface tension to form a jet stream which rapidly volatilizes during the jetting process, thereby causing the stream to fall on a collecting device to form a felted or flocculent random fibre.

FIG. 1 is a schematic structural view of an electrospinning apparatus used in the production of a fiber layer according to the present invention. The above steps S501 to S503 may be performed by an electrospinning apparatus as shown in fig. 1. First, the spinning solution prepared in step S501 is fed into the capillary injection needle 101. Capillary injection needle 101 comprises a hollow barrel 102, with a needle 103 at one end of barrel 102 and a pusher 104 at the other end. Further, the pressure is applied to the spinning solution by the propeller 104, and the spinning solution is injected into the collecting drum 106, which is continuously rolling, through the needle 103. Wherein a high voltage electric field is applied between the capillary injection needle 101 and the collecting roller 106. The spinning solution injected from the needle 103 forms a jet stream 105 under the action of a high-voltage electric field and is collected by a collecting roller 106. The jet stream 105 adheres to the inner wall of the collection cylinder 106 under centrifugal force and can form a layer of random batt fiber.

It will be appreciated that the type of capillary injection needle can be selected and adjusted by one skilled in the art according to the actual needs. Preferably, the capillary injection needle is 20 gauge.

It will be appreciated that the diameter of the fibre layer is influenced not only by the diameter of the capillary needle 101, the speed of advancement of the pusher 104, and the voltage of the high voltage electric field, but also by the size of the collection roller 106, the relative distance from the capillary needle 101, and the speed of rolling. The diameter of the fiber layer can be controlled by selecting and adjusting the above parameters according to actual needs by those skilled in the art.

Preferably, the advancing speed of the capillary needle is 2 ml/h-4 ml/h, the distance between the capillary needle and the collecting roller is 16 cm-18 cm, the rotating speed of the collecting roller is 300 rpm-400 rpm, the length of the collecting roller is 240 mm-260 mm, and the diameter of the collecting roller is 80 mm-100 mm.

Preferably, the first and second fibrous layers are respectively random batt fibers having a diameter of 10 microns to 20 microns.

In the related art, in order to facilitate recycling of the aluminum foil, a water-soluble polymer film layer (e.g., a mixture of a vinylpyrrolidone-acrylamide copolymer and sodium polyacrylate) is usually added between the polymer film layer and the aluminum foil, and the aluminum foil is separated from the polymer film layer by using the property that the water-soluble polymer film layer is soluble in hot water. However, it has problems: the water-soluble polymer layer of the monolithic structure results in a reduced bond strength between the polymer film layer and the aluminum foil layer, and the aluminum foil package is susceptible to delamination in a high temperature and high humidity environment or when heated (such as in a steamer or immersed in hot water).

To solve this problem, the embodiment of the present invention replaces the complete water-soluble polymer film layer in the related art with a batt fiber layer. The first fiber layer and the second fiber layer prepared by the embodiment of the invention are aramid fibers containing polyacrylamide. First, the flocculent fiber layer prepared by the electrospinning process according to the embodiment of the present invention covers only a portion of the surface of the aluminum foil, thereby allowing the polymer film layer and the aluminum foil to be in direct contact and adhered to each other to some extent to improve the bonding strength between the polymer film layer and the aluminum foil. Further, since polyacrylamide, which is a water-soluble polymer, is uniformly distributed in the aramid fiber, the fiber layer spun through steps S501 to S503 is changed from a state in which the surface is originally dense and smooth to a state in which it is loose and porous when it encounters water. Therefore, when the packaging material needs to be recycled, the packaging material can be soaked in water or other similar solvents, related processes such as stirring or heating are assisted, the fiber layer is partially dissolved after meeting water, the connection tightness between the polymer film layer and the aluminum foil is reduced, and the polymer layer and the aluminum foil can be conveniently peeled off from each other by utilizing the property that the fiber layer is partially dissolved and subjected to form change (dense and porous) after meeting water, so that the recycling of the aluminum foil layer is facilitated. In summary, the embodiment of the invention can realize mutual peeling of the polymer layer and the aluminum foil on the basis of ensuring the stability and the durability of the aluminum foil package, thereby facilitating the recycling of the aluminum foil layer.

In some embodiments of the present invention, S100 includes:

Specifically, S101 includes:

according to the following formula: polyoxyethylene polyoxypropylene pentaerythritol ether: 2-amino-2-methyl-1-propanol: phenolic resin: acrylic resin: pinene resin = (2-4): (2-4): (2-4): (10-20): (20-30): 100 parts by mass of aminopropyltrimethoxysilane, polyoxyethylene polyoxypropylene pentaerythritol ether, 2-amino-2-methyl-1-propanol, a phenol resin, an acrylic resin and a pinene resin were mixed to obtain a first mixture.

The pinene resin is also called terpene resin, and is linear polymer obtained by using alpha pinene or beta pinene of turpentine oil and through cationic polymerization under the action of Friedel-crafts catalyst. The pinene resin functions in the above steps to impart good viscosity and adhesive strength to the first adhesive. Aminopropyl trimethoxy silane is used as a coupling agent, so that the viscosity and the bonding strength of the first adhesive can be further improved. Polyoxyethylene polyoxypropylene pentaerythritol ether is used as a defoaming agent. 2-amino-2-methyl-1-propanol is used as a buffer to adjust the pH of the first binder. And (2) mixing and extruding the first mixture through a screw extrusion device by adopting the temperature condition of 110-120 ℃ in the step S102 according to the components and the proportion of the first mixture in the step S101 to obtain the first adhesive. In step S103, a first adhesive coating may be applied to the first surface of the aluminum foil layer by mechanical spraying or brushing. It will be appreciated that after the first adhesive is applied, the first fibre layer can then be laid as soon as possible to avoid curing of the first adhesive. Through the components and the process, the first adhesive with proper viscosity and excellent bonding performance can be obtained.

In some embodiments of the present invention, S200 includes:

s201, mixing and extruding calcium propionate, methyl p-hydroxybenzoate, vinyl pyrrolidone-vinyl acetate copolymer, polyethylene resin and polypropylene resin at 180-200 ℃ to obtain a polymer outer layer in a molten state;

Specifically, S201 includes:

according to the weight ratio of calcium propionate: methyl p-hydroxybenzoate: vinylpyrrolidone-vinyl acetate copolymer: polyethylene resin: polypropylene resin = (2-4): (2-4): (20-30): (70-80): 100, mixing and extruding the calcium propionate, the methyl p-hydroxybenzoate, the vinyl pyrrolidone-vinyl acetate copolymer, the polyethylene resin and the polypropylene resin at the temperature of 180-200 ℃ to obtain the polymer outer layer in a molten state.

It is understood that the polymer outer layer of the embodiments of the present invention is a mixture of polypropylene resin and polyethylene resin. The vinyl pyrrolidone-vinyl acetate copolymer is used for adjusting and improving the surface activity of polyethylene resin and polypropylene resin. Calcium propionate was used as a fungicide. And (2) according to the components and the proportion of the first mixture in the step S201, mixing and extruding at the temperature of 180-200 ℃ in the step S202 to obtain a polymer outer layer.

It will be appreciated that the second adhesive may be any one of an epoxy adhesive, or a phenolic adhesive, or a polyurethane adhesive, or an allyl adhesive.

In some implementations of the embodiments of the present invention, S400 includes:

In step S401, the raw material mixture ratio is talcum powder: beeswax: polyvinyl alcohol resin: polylactic acid resin = (4-6): (4-6): (70-80): 100.

the packaging material obtained in the above steps is particularly suitable for the packaging of liquid foods or pharmaceutical products (e.g. oral liquids, soups, dairy products, etc.). In the case of the above-mentioned types of foods or medicines, the problem of difficulty and waste in sucking or pouring is caused by the tendency to stick a cup inside the packaging material due to flowability, viscosity, surface tension, and the like. In order to solve the above problems, embodiments of the present invention employ a means of improving the lubricating properties of the polymer inner layer. The polylactic resin is plant-derived resin which takes plant starch and sugar as raw materials, and has relatively excellent degradability and biological-friendly performance. The wax-like nature of beeswax can improve the water resistance and sealing properties of the inner polymer layer. The main component of talcum powder is magnesium silicate hydrate, and because the crystal structure of the talcum powder is in a layered state, the talcum powder has the tendency of being easily cracked into scales and special lubricating property. By adding the talcum powder, the lubricating property of the inner polymer layer can be effectively improved, and the phenomenon that liquid food or medicines are stained in a cup can be reduced or avoided.

In order to further improve the product quality of the packaging material of the embodiment of the present invention, in some embodiments of the embodiment of the present invention, the following steps S301 to S305 may be adopted to prepare a second adhesive, the second adhesive is adopted to realize the bonding of the second fiber layer of step S306, and after the bonding is completed, the polymer inner layer is applied by coating through the following steps S401 to S404.

S300 comprises the following steps:

s301, dropwise adding ammonia water into the ferric trichloride aqueous solution, stirring, standing after dropwise adding, collecting precipitate, cleaning, and filtering to obtain colloidal ferric hydroxide;

s302, adding aminopropyl trimethoxy silane and ferric hydroxide into a titanium tetrachloride water solution, and uniformly mixing by ultrasonic waves to obtain a second mixture;

s303, dropwise adding a sodium hydroxide aqueous solution into the second mixture, stirring until the pH value of the second mixture reaches 12-13, standing after dropwise adding, collecting precipitates, cleaning, filtering and calcining to obtain modified iron oxide;

s304, ultrasonically emulsifying the modified iron oxide and the palm oil uniformly in water to obtain a third mixture;

s305, uniformly mixing the third mixture, polycarbodiimide, epoxy acrylate and terpene resin, performing microwave treatment to remove moisture, mixing and extruding to obtain a second adhesive;

s306, coating a second adhesive on the second surface of the aluminum foil layer, and laying a second fiber layer on the second surface.

In step S301, the concentration of the ferric trichloride aqueous solution is 8wt% -10wt%, the concentration of the ammonia water is 12% -14%, and the standing time is 20 minutes-40 minutes.

In step S302, the mixture ratio of the raw materials is aminopropyltrimethoxysilane: iron hydroxide: titanium tetrachloride aqueous solution = (2-4): (12-14): 100, the concentration of the titanium tetrachloride aqueous solution is 240g/l-260g/l, and the power and time of ultrasonic mixing can be selected by the skilled person, so that uniform dispersion can be realized.

In step S303, the concentration of the sodium hydroxide aqueous solution is 8% -10%, the standing time is 20-40 minutes, and the calcining temperature is 520-540 ℃ for 2-2.5 hours.

In step S304, the raw materials are modified ferric oxide: palm oil: water = (20-25): (20-30): 100. the power and time of phacoemulsification may be selected by one skilled in the art to achieve sufficient emulsification.

In step S305, the mixture ratio of the raw materials is a third mixture: polycarbodiimide: epoxy acrylate: terpene resin = (20-30): (20-30): (40-50): 100, and the temperature condition of mixing is 120-140 ℃.

S400 includes:

s402, coating the inner polymer layer in a molten state on a second fiber layer;

s403, uniformly applying a magnetic field to the polymer inner layer along the direction vertical to the second surface;

and S404, after the magnetic field is removed, naturally cooling the inner polymer layer to room temperature.

in step S403, the magnetic field is applied for 4 to 6 seconds, and the field strength is 200 to 300 oersted.

In step S301, ferric chloride solution reacts chemically with ammonia water to generate colloidal ferric hydroxide precipitate (i.e., ferric hydroxide sol), in step S302, ferric hydroxide and aminopropyltrimethoxysilane serving as a coupling agent are added to a titanium tetrachloride aqueous solution to obtain a mixture of ferric hydroxide and titanium tetrachloride, in step S303, titanium ions in the titanium tetrachloride are combined with hydroxyl groups by adjusting the mixture to be alkaline to generate titanium hydroxide precipitate, and the titanium hydroxide is uniformly deposited and coated on the surface of the colloidal ferric hydroxide, thereby obtaining the ferric hydroxide particles (i.e., modified iron oxide) coated with titanium hydroxide by a chemical wet method. In step S304, by ultrasonically emulsifying the modified iron oxide and the palm oil and water, the surface energy of the modified iron oxide can be changed so that it is more easily dispersed in the resin material. In step S305, the modified iron oxide-containing adhesive (i.e., the second adhesive) can be obtained by mixing and kneading the third mixture containing modified iron oxide with polycarbodiimide, epoxy acrylate, and terpene resin.

It will be appreciated that the time interval between steps S306 and S402 is short, and that after the second adhesive is applied and the second fiber layer is laid, the polymer inner layer in a molten state needs to be quickly applied to the second fiber layer. Therefore, the preparation of the raw materials in each step can be completed in advance, so that the steps S306 and S402 are performed quickly and continuously after the raw materials are prepared. Preferably, the execution time interval of steps S306 and S402 is less than or equal to 15 seconds.

The magnetic field may be applied in a state where the second adhesive and the polymer inner layer are not yet cured by S403. The second adhesive contains magnetic modified iron oxide. Under the action of a magnetic field, the modified iron oxide drives the second adhesive to generate a tendency of penetrating through the flocculent second fiber layer and flowing towards the uncured polymer inner layer, so that the second adhesive and the second fiber layer are more fully contacted and more closely attached and bonded with the polymer inner layer, and the purpose of effectively avoiding the problems of stripping and layering of the polymer inner layer in the using process is achieved.

In addition, the surface of the modified iron oxide is coated with titanium oxide, the titanium oxide can improve the antibacterial and bacteriostatic performance of the packaging material, and the titanium oxide can cover the surface color of the iron oxide, so that the direct contact between the iron oxide and the polymer is avoided, and the inner layer of the polymer is ensured to keep ideal color and glossiness.

The following will describe the method for producing the packaging material of the present invention in detail with reference to specific examples. Examples 1 to 4 samples of packaging material were prepared. Among them, the second adhesives used in examples 1 and 2 do not contain iron oxide and do not include a step of applying a magnetic field to the polymer inner layer. The second adhesive used in examples 3 and 4 contained iron oxide and included the step of applying a magnetic field to the polymer inner layer. Examples 5 and 6 2 magnetic additives containing iron oxide were prepared, and the magnetic additives were added to the second binders in example 3 (using the magnetic additive of example 5) and example 4 (using the magnetic additive of example 6), respectively. The raw materials in the following examples were all obtained by commercial procurement.

Examples 1 and 2

The embodiment provides a preparation method of a packaging material, which comprises the following steps:

s601, preparing raw materials required for preparing a polymer outer layer, a polymer inner layer, a first adhesive, a second adhesive, a first fiber layer and a second fiber layer according to the proportion in a table 1;

s602, mixing polyacrylamide and poly (p-phenylene terephthalamide) and dissolving the mixture in a dimethyl acetamide solvent to prepare a spinning solution with the concentration of 11 wt%; the spinning solution is sent into a capillary injection needle and pushed into the capillary injection needle, and a 13 kV direct-current electric field is applied between the capillary injection needle and a collecting roller; taking out and spreading the collected matter in the collecting roller to obtain a first fiber layer and a second fiber layer;

s603, mixing aminopropyl trimethoxy silane, polyoxyethylene polyoxypropylene pentaerythritol ether, 2-amino-2-methyl-1-propanol, phenolic resin, acrylic resin and pinene resin, mixing at 110-120 ℃, extruding to the surface of the aluminum foil layer, uniformly coating, and paving a first fiber layer after coating;

s604, mixing and extruding calcium propionate, methyl p-hydroxybenzoate, vinyl pyrrolidone-vinyl acetate copolymer, polyethylene resin and polypropylene resin at the temperature of 180-200 ℃ until the surface of the first fiber layer is uniformly coated, and naturally cooling to room temperature;

s605, uniformly mixing polycarbodiimide, epoxy acrylate and terpene resin, performing microwave treatment to remove moisture, mixing at 120-140 ℃, extruding to the surface of the aluminum foil layer, uniformly coating, and paving a second fiber layer after coating;

and S606, mixing and extruding the talcum powder, the beeswax, the polyvinyl alcohol resin and the polylactic acid resin at 220-240 ℃, uniformly coating the mixture on the surface of the second fiber layer, and naturally cooling to room temperature.

Example 3 and example 4

s701, preparing raw materials required for preparing a polymer outer layer, a polymer inner layer, a first adhesive, a second adhesive, a first fiber layer and a second fiber layer according to the proportion in a table 1;

s702, mixing polyacrylamide and poly (p-phenylene terephthalamide) and dissolving the mixture in a dimethylacetamide solvent to prepare a spinning solution with the concentration of 11 wt%; feeding the spinning solution into a capillary injection needle and pushing the capillary injection needle, wherein a 13 kV direct current electric field is applied between the capillary injection needle and a collecting roller; taking out and spreading the collected matter in the collecting roller to obtain a first fiber layer and a second fiber layer;

s703, mixing aminopropyl trimethoxysilane, polyoxyethylene polyoxypropylene pentaerythritol ether, 2-amino-2-methyl-1-propanol, phenolic resin, acrylic resin and pinene resin, mixing at 110-120 ℃, extruding to the surface of the aluminum foil layer, uniformly coating, and paving a first fiber layer after coating;

s704, mixing and extruding calcium propionate, methyl p-hydroxybenzoate, vinyl pyrrolidone-vinyl acetate copolymer, polyethylene resin and polypropylene resin at 180-200 ℃ until the surface of the first fiber layer is uniformly coated, and naturally cooling to room temperature;

s705, uniformly mixing the magnetic additive, the polycarbodiimide, the epoxy acrylate and the terpene resin, carrying out microwave treatment to remove moisture, mixing at 120-140 ℃, extruding to the surface of the aluminum foil layer, uniformly coating, and paving a second fiber layer after coating;

s706, mixing talcum powder, beeswax, polyvinyl alcohol resin and polylactic acid resin at 220-240 ℃, extruding the mixture to the surface of the second fiber layer, uniformly coating the mixture, uniformly applying a 300 oersted magnetic field to the inner polymer layer along the direction perpendicular to the second fiber layer (which is equal to the direction perpendicular to the second surface), wherein the application time is 6 seconds, and naturally cooling the inner polymer layer to room temperature after the magnetic field is removed.

The magnetic additive of example 5 was used in example 3, and the magnetic additive of example 6 was used in example 4.

TABLE 1

Example 5

S801, dropwise adding 12% ammonia water into 8wt% ferric trichloride aqueous solution, stirring, standing for 20 minutes after dropwise adding, collecting precipitate, cleaning, and filtering to obtain colloidal ferric hydroxide;

s802, according to the amino propyl trimethoxy silane: iron hydroxide: titanium tetrachloride aqueous solution =2:12:100, adding aminopropyl trimethoxy silane and ferric hydroxide into 240g/l titanium tetrachloride water solution, and uniformly mixing by ultrasonic waves to obtain a second mixture;

s803, dropwise adding 8% sodium hydroxide aqueous solution into the second mixture, stirring until the pH value of the second mixture is 12-13, standing for 20 minutes after dropwise adding, collecting precipitates, cleaning, filtering, and calcining for 2.5 hours at the temperature of 520 ℃ to obtain modified iron oxide;

s304, modifying iron oxide: palm oil: water =20:30: and (3) carrying out ultrasonic emulsification on the modified iron oxide and the palm oil in water according to the mass ratio of 100 to obtain a third mixture, wherein the third mixture is the magnetic additive.

Example 6

S901, dropwise adding 14% ammonia water into a 10wt% ferric trichloride aqueous solution, stirring, standing for 40 minutes after dropwise adding, collecting precipitates, cleaning, and filtering to obtain colloidal ferric hydroxide;

s902, according to the formula of aminopropyl trimethoxy silane: iron hydroxide: titanium tetrachloride aqueous solution =4:14:100, adding aminopropyl trimethoxy silane and ferric hydroxide into a titanium tetrachloride water solution with the concentration of 260g/l, and uniformly mixing by ultrasonic waves to obtain a second mixture;

s903, dropwise adding a 10% sodium hydroxide aqueous solution into the second mixture, stirring until the pH value of the second mixture is 12-13, standing for 40 minutes after dropwise adding, collecting precipitates, cleaning, filtering, and calcining for 2 hours at 540 ℃ to obtain modified iron oxide;

s904, according to the modified iron oxide: palm oil: water =25:25: and (3) carrying out ultrasonic emulsification on the modified iron oxide and the palm oil in water according to the mass ratio of 100 to obtain a third mixture, wherein the third mixture is the magnetic additive.

Performance testing

After the packaging material prepared in example 1 is soaked in water at 85 ℃ for 60 minutes, the outer layer and the aluminum foil layer are peeled off, and a microscopic electron microscope image of one side surface of the aluminum foil layer after peeling is shown in fig. 2. As is evident from fig. 2, the fibrous layer partially dissolved after immersion in water, forming loose porous fibers.

The samples prepared in examples 1 to 4 were tested for peel strength using the national standard GB/T8808-1988. The samples were cut into test specimens of 15 mm by 200 mm. The results are shown in Table 2.

TABLE 2

The results show that the samples prepared in examples 3 and 4 have higher peeling difficulty than those prepared in examples 1 and 2, the interlayer bonding between the materials of the layers is tighter, and the bonding strength is firm.

The samples prepared in examples 1 to 4 were further tested by cutting them into 1 mm x 10 mm test strips and manually peeling the polymer layer and the aluminum foil layer after soaking in water at 85 degrees celsius, the results are shown in table 3.

TABLE 3

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method of making a packaging material, the method comprising:

s400, coating the inner polymer layer in a molten state on the second fiber layer and cooling to obtain the packaging material;

wherein the first fiber layer and the second fiber layer are prepared by the following steps:

s501, according to the weight ratio of polyacrylamide: poly (paraphenylene terephthalamide) = (30-40): 100, mixing the polyacrylamide and the poly-p-phenylene terephthalamide, and dissolving the mixture in a dimethylacetamide solvent to prepare a spinning solution with the concentration of 10-12 wt%;

s502, feeding the spinning solution into a capillary injection needle and pushing the capillary injection needle to spray the spinning solution to a rolling and grounded collecting roller, wherein a 12-14 kV direct-current electric field is applied between the capillary injection needle and the collecting roller which are spaced from each other;

s503, taking out the collected object in the collecting roller and spreading to obtain a fiber layer.

2. The method of claim 1, wherein the first fiber layer and the second fiber layer are each random batt fibers having a diameter of 10-20 microns.

3. The production method according to claim 1,

the advancing speed of the capillary injection needle is 2 ml/h-4 ml/h; and/or

The distance between the capillary injection needle and the collecting roller is 16 cm-18 cm; and/or

The rotating speed of the collecting roller is 300-400 revolutions/minute; and/or

The length of the cylinder body of the collecting roller is 240 mm-260 mm; and/or

The diameter of the collecting roller is 80 mm-100 mm.

4. The production method according to any one of claims 1 to 3, wherein the S100 includes:

s102, mixing and extruding the first mixture to obtain the first adhesive;

s103, coating the first adhesive on the first surface of the aluminum foil layer, and paving the first fiber layer on the first surface.

5. The production method according to claim 4,

in said S101, the molar ratio of aminopropyltrimethoxysilane: polyoxyethylene polyoxypropylene pentaerythritol ether: 2-amino-2-methyl-1-propanol: phenolic resin: acrylic resin: pinene resin = (2-4): (2-4): (2-4): (10-20): (20-30): 100, mixing the aminopropyltrimethoxysilane, the polyoxyethylene polyoxypropylene pentaerythritol ether, the 2-amino-2-methyl-1-propanol, the phenolic resin, the acrylic resin and the pinene resin;

in the step S102, the temperature condition of the mixing is 110-120 ℃.

6. The method according to any one of claims 1 to 3, wherein the S200 includes:

s202, coating the outer polymer layer in a molten state on the first fiber layer and naturally cooling to room temperature.

7. The method according to claim 6, wherein in S201, the ratio of calcium propionate: methyl paraben: vinylpyrrolidone-vinyl acetate copolymer: polyethylene resin: polypropylene resin = (2-4): (2-4): (20-30): (70-80): 100 by mass, the calcium propionate, the methyl paraben, the vinylpyrrolidone-vinyl acetate copolymer, the polyethylene resin, and the polypropylene resin are kneaded and extruded.

8. The method according to any one of claims 1 to 3, wherein the S400 includes:

s402, coating the inner polymer layer in the molten state on the second fiber layer and cooling to obtain the packaging material.

9. Packaging material, characterized in that it is obtained with a production method according to any one of claims 1 to 8.

10. A packaging container, characterized in that it is produced using the packaging material according to claim 9.