Composite food packaging material and preparation method thereof

Abstract

The invention discloses a composite food packaging material and a preparation method thereof, relates to the field of food packaging materials, aims to provide a multifunctional and degradable packaging material, and adopts the technical scheme that a paper base or a PLA base is taken as a base material, and ESO, edible wax, an antibacterial agent, a reinforcing agent and an antioxidant are compounded. The ESO and the edible wax are compounded on the base material, the ESO can improve the film-forming property and the barrier property of the wax, and the ESO and the edible wax can improve the hydrophobicity of the base material and achieve a degradable effect. ESO can play a plasticizing role, prevent a wax layer from cracking and improve the flexibility of a base material, and further, epoxy groups of ESO can capture free radicals and prolong the shelf life of food. The antibacterial agent and the antioxidant enable the packaging material to have various functions, and the reinforcing agent can further reinforce the strength of the packaging material.

Description

Technical Field

[0001] This invention relates to the field of food packaging materials technology, specifically to a composite food packaging material and its preparation method. Background Technology

[0002] Existing food packaging materials mainly include LDPE plastic, PP plastic, pure paper packaging, and PLA (polylactic acid) plastic. Among these materials, LDPE and PP plastics have problems such as non-degradability and serious environmental pollution. Pure paper packaging has poor hydrophobicity and requires PE coating, but PE coating is non-degradable. PLA plastic has problems such as high cost, brittleness, and insufficient barrier properties. To solve these problems, wax-coated paper, PLA / starch blend film, and coatings containing synthetic additives have been further improved. However, wax-coated paper has problems such as poor mechanical properties and limited functionality, PLA / starch blend film has problems of insufficient hydrophobicity and oxygen barrier properties, and coatings containing synthetic additives may migrate harmful substances. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a composite food packaging material and its preparation method, which can effectively solve the problems in the background art.

[0004] To achieve the above objectives, the present invention first discloses a composite food packaging material. The technical solution adopted includes a substrate and functional components. The substrate includes either a paper base or a PLA substrate. The paper base can be virgin pulp paper, kraft paper, etc. with a basis weight of 80-200 g / m². The PLA substrate is a polylactic acid film or a polylactic acid injection molded container with a thickness of 50-100 μm.

[0005] The functional components include 50-80 parts by weight of main film-forming agent, 5-20 parts by plasticizer, and 4-13 parts by weight of functional additives, including photoinitiators. The functional components are attached to the substrate or co-extruded with the substrate.

[0006] As a preferred embodiment of the present invention, the main film-forming agent is an edible wax, such as beeswax or palm wax.

[0007] As a preferred embodiment of the present invention, the plasticizer is epoxidized soybean oil (ESO).

[0008] As a preferred embodiment of the present invention, the functional additive further includes antibacterial agents, enhancers, and antioxidants.

[0009] As a preferred embodiment of the present invention, the antibacterial agent comprises 1-5 parts by weight of chitosan or 0.1-0.5 parts by weight of nisin.

[0010] As a preferred embodiment of the present invention, the reinforcing agent is 3-10 parts of nanocellulose.

[0011] As a preferred embodiment of the present invention, the antioxidant is 1-2 parts of rosemary extract or vitamin E.

[0012] This invention also discloses a method for preparing the above-mentioned composite food packaging material, the technical solution of which includes the following steps: Step 1, preparation of functional components, After the main film-forming agent and plasticizer are melt-mixed, functional additives are added and dispersed evenly. Step 2, Substrate pretreatment, For paper-based substrates, pretreatment is performed using plasma treatment; For PLA substrates, pretreatment is performed by corona treatment or by applying a primer. Step 3, compounding. For paper-based substrates, the functional components obtained in step 1 are coated onto the surface of the pretreated substrate and then cooled and cured. For PLA substrate, the functional components obtained in step 1 are cast and compounded with the pretreated substrate to form a film, or co-extruded and blown into a film with the pretreated substrate. Step 4, Post-processing The composite material obtained in step 3 is then UV cured.

[0013] As a preferred embodiment of the present invention, in step 4, a UV curing machine is used to irradiate the material for 3-5 seconds with a light source power of 150-200 W / cm; the photoinitiator is 1-hydroxycyclohexylphenyl ketone.

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: By compounding ESO and edible wax onto a substrate, ESO enhances the film-forming properties and barrier properties of the wax, while both improve the hydrophobicity of the substrate and achieve biodegradability. Furthermore, ESO acts as a plasticizer, preventing wax layer cracking and improving the flexibility of the substrate. Additionally, the epoxy groups of ESO can capture free radicals, extending the shelf life of food. Antibacterial and antioxidant agents diversify the functions of the packaging material, while reinforcing agents further strengthen the packaging material. Detailed Implementation

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1 This embodiment discloses the first implementation of the present invention, which first discloses a composite food packaging material. The technical solution adopted includes a base material and functional components. The base material is a 180 g / m² food-grade pulp paper cup. The functional components include, by weight, 65 parts beeswax, 15 parts ESO, 10 parts nanocellulose, 5 parts chitosan, 2 parts rosemary extract, and 0.1 parts 1-hydroxycyclohexylphenyl ketone.

[0017] This embodiment also discloses a method for preparing the above-mentioned composite food packaging material, the technical solution of which includes the following steps: Step 1, preparation of functional components, After beeswax and ESO are melt-mixed, nanocellulose, chitosan, rosemary extract and 1-hydroxycyclohexylphenyl ketone are added and dispersed evenly; Step 2, Substrate pretreatment, Plasma treatment is applied to the virgin pulp paper cups to improve coating adhesion; Oxygen was injected at a power of 180W at a distance of 10mm from the paper cup, with a spray speed of 10 m / min. Step 3, compounding. The functional components obtained in step 1 are sprayed onto the surface of the pretreated pulp paper cup and then cooled and cured. Step 4, Post-processing The composite material obtained in step 3 is then UV cured; Using a UV curing machine, ESO is cured by irradiating with a light source power of 150 W / cm for 5 seconds to reduce ESO migration.

[0018] The paper cups produced in this embodiment can be used for yogurt packaging.

[0019] Example 2 This embodiment discloses a second implementation of the present invention. First, a composite food packaging material is disclosed. The technical solution adopted includes a substrate and functional components. The substrate is a PLA film with a thickness of 80 μm. The functional components include, by weight, 70 parts palm wax, 20 parts ESO, 0.3 parts Nisin, 1 part vitamin E, and 0.1 parts 1-hydroxycyclohexylphenyl ketone.

[0020] This embodiment also discloses a method for preparing the above-mentioned composite food packaging material, the technical solution of which includes the following steps: Step 1, preparation of functional components, After melting and mixing palm wax with ESO, Nisin, vitamin E and 1-hydroxycyclohexylphenyl ketone are added and dispersed evenly; Step 2, Substrate pretreatment, The PLA film was subjected to corona treatment; The substrate surface was treated using an online corona treatment machine with a voltage of 10kV and a current of 0.4A at a processing speed of 20 m / min and a discharge frequency of 80Hz. Step 3, compounding. The functional components obtained in step 1 are cast onto the surface of the pretreated PLA film using a casting laminating machine. The extrusion temperature of the casting laminating machine is 90°C, the cooling roller temperature is 25°C, the lamination speed is 15m / min, and the lamination pressure is 0.3 MPa. Step 4, Post-processing The composite material obtained in step 3 is then UV cured; Using a UV curing machine, ESO is cured by irradiating with a light source power of 200 W / cm for 3 seconds to reduce ESO migration.

[0021] The packaging material prepared in this embodiment can be used as a salad box.

[0022] Performance tests were conducted on Examples 1 and 2: index Example 1 Example 2 Pure PLA membrane PE coated paper Water contact angle 112° 121° 70° 95° oxygen permeability 8 cm³ / m²·day 7 cm³ / m²·day 500 cm³ / m²·day 2000 cm³ / m²·day Degradability 3-6 months (fully degraded) 3-6 months (fully degraded) 6-12 months (fully degraded) Non-degradable cost Low middle high middle The above comparison shows that, compared with the prior art, Examples 1 and 2 have a higher water contact angle, better hydrophobicity, lower oxygen permeability, higher barrier properties, better degradability, and lower cost.

[0023] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A composite food packaging material, characterized in that: The product includes a substrate and functional components. The substrate is either a paper-based substrate or a PLA substrate. The functional components include 50-80 parts by weight of a main film-forming agent, 5-20 parts by weight of a plasticizer, and 4-13 parts by weight of a functional additive, including a photoinitiator. The functional components are attached to the substrate or co-extruded with the substrate.

2. The composite food packaging material according to claim 1, characterized in that: The main film-forming agent is edible wax.

3. The composite food packaging material according to claim 1, characterized in that: The plasticizer is epoxidized soybean oil.

4. The composite food packaging material according to claim 1, characterized in that: The functional additives also include antibacterial agents, enhancers, and antioxidants.

5. The composite food packaging material according to claim 4, characterized in that: The antibacterial agent comprises 1-5 parts by weight of chitosan or 0.1-0.5 parts by weight of nisin.

6. The composite food packaging material according to claim 4, characterized in that: The reinforcing agent is 3-10 parts of nanocellulose.

7. The composite food packaging material according to claim 4, characterized in that: The antioxidant is 1-2 parts of rosemary extract or vitamin E.

8. A method for preparing the composite food packaging material as described in claim 1, characterized in that, Includes the following steps: Step 1, preparation of functional components, After the main film-forming agent and plasticizer are melt-mixed, functional additives are added and dispersed evenly. Step 2, Substrate pretreatment, For paper-based substrates, pretreatment is performed using plasma treatment; For PLA substrates, pretreatment is performed by corona treatment or by applying a primer. Step 3, compounding. For paper-based substrates, the functional components obtained in step 1 are coated onto the surface of the pretreated substrate and then cooled and cured. For PLA substrate, the functional components obtained in step 1 are cast and compounded with the pretreated substrate to form a film, or co-extruded and blown into a film with the pretreated substrate. Step 4, Post-processing The composite material obtained in step 3 is then UV cured.

9. The preparation method according to claim 8, characterized in that: In step 4, a UV curing machine is used to irradiate the product with a light source power of 150-200 W / cm for 3-5 seconds; the photoinitiator used is 1-hydroxycyclohexylphenyl ketone.