CN111907177A

CN111907177A - Recyclable composite packaging material, recyclable composite packaging bag and recycling method thereof

Info

Publication number: CN111907177A
Application number: CN202010801730.7A
Authority: CN
Inventors: 张逢辉
Original assignee: Ld Packaging Co ltd
Current assignee: Ld Packaging Co ltd
Priority date: 2020-08-11
Filing date: 2020-08-11
Publication date: 2020-11-10

Abstract

The invention provides a recyclable composite packaging material, which comprises a film body, wherein the film body is formed by compounding an outer layer and an inner layer, the outer layer and the inner layer are prepared by mixing at least two materials of HDPE, MDPE, LDPE, mPE and vinyl-containing copolymer, and an opening agent and/or a slipping agent are/is added into the outer layer and the inner layer; the invention provides a composite packaging film, which is applied to the composite packaging material; the invention also provides a composite packaging bag and a recovery method thereof. Compared with the prior art, the recyclable composite packaging material has simple components and is convenient to recycle; the composite packaging bag is convenient to recycle; the recovery method has lower technical difficulty in the recovery and reconstruction process, and has lower recovery cost and reconstruction cost.

Description

Recyclable composite packaging material, recyclable composite packaging bag and recycling method thereof

Technical Field

The invention relates to the field of packaging bags, in particular to a recyclable composite packaging material, a composite packaging bag and a recycling method thereof.

Background

Because the plastic has low cost and good ductility, the existing packaging material is mostly made of plastic films, but partial film packages are difficult to degrade, so that white pollution is caused to influence the ecological environment, the recovery difficulty is high due to the complex components of the film packages, and the regeneration path of the recovered product is also limited, so that the packaging material which has low recovery difficulty and is convenient to regenerate and utilize is urgently needed.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a recyclable composite packaging material which is simple in composition and convenient to recycle.

In order to achieve the purpose, the invention adopts the following technical scheme:

the recyclable composite packaging material comprises a film body, wherein the film body is formed by compounding an outer layer and an inner layer, the outer layer and the inner layer are both prepared by mixing at least two materials of HDPE, MDPE, LDPE, mPE and vinyl-containing copolymer, and an opening agent and/or a slipping agent are/is added into the outer layer and the inner layer.

Compared with the prior art, the recyclable composite packaging material has the following beneficial effects:

(1) the main components of the composite packaging material are at least two materials of HDPE, MDPE, LDPE, mPE and vinyl-containing copolymer, and the raw material is ethylene polymer or vinyl-containing copolymer, so that the main component of the composite packaging material is still the ethylene polymer or vinyl-containing copolymer after being recovered, and the composite packaging material can be subsequently processed into other vinyl-containing products through reconstruction, therefore, the recyclable composite packaging material has strong reproducibility, low recycling difficulty and low recycling cost and reconstruction cost; in addition, the composite packaging material has simple raw materials and stable physical and chemical properties, can carry out secondary processing and modification on the recycled material, ensures that the product produced secondarily has good performance, and ensures that the composite packaging material can be recycled to be reproduced into a product with higher use requirement, thereby reducing the investment of new raw materials and reducing the consumption of petroleum resources;

(2) the composite packaging material is added with the opening agent and/or the slipping agent, so that the static friction coefficient/dynamic friction coefficient of the composite packaging material is changed, the adhesion stability and the surface smoothness of the internal structure of the material are improved, the anti-adhesion performance, the demolding performance, the anti-static performance, the anti-pollution and anti-damage performance and the surface highlight performance (the coloring performance and the carbon black dispersibility are changed) are improved, the composite packaging material obtains excellent surface performance, physical and chemical stability, the composite packaging material is ensured to be suitable for being recycled, and a good phase is kept after being recycled;

(3) the addition of the opening agent and/or the slipping agent of the composite packaging material can play a role in smoothing and leveling the ink added into the secondary product, improve the dispersibility of the ink, avoid the ink from settling and caking, and simultaneously ensure that the ink is tightly attached to the product, so that the characters and patterns on the secondary product are clear and visible, and the color is bright.

Preferably, the outer layer at least comprises HDPE and LDPE, wherein the weight percentage of the HDPE is 60-90%, and the weight percentage of the LDPE is 10-30%; the inner layer at least comprises LDPE and mPE, wherein the weight percentage of the LDPE is 40-80%, and the weight percentage of the mPE is 10-50%.

The outer layer mainly comprises HDPE and LDPE, so that the outer layer is kept in good thermoplasticity, and simultaneously, the HDPE has good stiffness, flatness and high temperature resistance compared with other PE materials, so that the attractiveness and the use performance of the outer layer are improved, the composite packaging material is not easy to damage, the composite packaging material is convenient to recycle, the processability can be improved due to the addition of the LDPE, and the quality of a secondary regeneration product is ensured; the inner layer mainly comprises LDPE and mPE, so that the inner layer has good biocompatibility while keeping good thermoplasticity, can contact food, has good low-temperature heat sealing performance, can be bonded to form a package under low-temperature heating, and reduces production energy consumption.

Preferably, the inner layer contains a copolymer containing a vinyl group, and the copolymer containing a vinyl group in the inner layer is POP.

The elasticity of the inner layer can be improved by adding POP (vinyl polymer grafted polyether polyol) into the inner layer, so that the inner layer has high bearing capacity and high modulus, and the invasion of bacteria caused by micropores on the surface of the inner layer during pulling is avoided, so that better coating, sealing and fresh-keeping effects can be provided for food; in addition, the inner layer, which is mainly composed of LDPE and POP, can be subjected to thermoplastic deformation at a lower heating temperature, so that the inner layer can be covered on the surface of food at a lower (110-120 ℃) heat sealing temperature, or two opposite inner layers can be heat sealed to form a bagged package.

Preferably, the outer layer and the inner layer are compounded through an adhesive layer; the composite packaging material can be formed by compounding the outer layer and the inner layer in a thermal compounding mode, and the compounding temperature during compounding the outer layer and the inner layer can be reduced by arranging the adhesive layer, or the composite molding can be realized without the thermal compounding mode, so that the production energy consumption is reduced.

Preferably, the inner side of the outer layer is subjected to corona treatment and then is compounded with the inner layer to form a film body; because the outer layer mainly comprises ethylene materials, the surface of the outer layer is smooth and high, and the ethylene materials are non-polar substances (the surface tension is low, so that ink/adhesive cannot be firmly attached), the surface energy of the inner side of the outer layer is changed by carrying out corona on the inner side of the outer layer, the surface polarity is increased, the firmness degree of the inner side of the outer layer after being bonded with the bonding layer is conveniently improved, and the separation of the outer layer and the inner layer caused by the falling of the bonding layer is avoided.

Preferably, a printing layer is arranged on the inner side of the outer layer, and patterns are printed on the printing layer; corona treatment has been carried out to bond line one side in advance to the outer layer, behind the printing layer, its printing ink can be stably attached to outer inboard, avoids the printing ink pattern because printing ink pine takes off and the distortion, and in addition, the printing layer is located between skin and the bond line, and the bond line can provide the bearing effect to the printing layer, further makes the printing layer adhesion at outer inboard to can improve composite packaging material's aesthetic property, avoid composite packaging material outward appearance too monotonous.

Preferably, the outer side of the outer layer is subjected to corona treatment and then is compounded with the inner layer to form a film body; because the ethylene material is a nonpolar substance, the surface polarity of the ethylene material is increased by carrying out corona on the outer side of the outer layer, the high temperature resistance of the outer side surface of the outer layer is improved (to 130-.

Another object of the present invention is to provide a composite packaging bag using the above recyclable composite packaging material, which includes a bag body made of the above packaging material, the bag body being provided with a receiving cavity having an upper end opened.

Another object of the present invention is to provide a recycling method for the recyclable composite packaging bag, which comprises the steps of:

(1) cleaning: cleaning the composite packaging bag, and then drying the composite packaging bag;

(2) crushing: shredding the composite packaging bag into pieces by using a film shredder;

(3) cleaning: washing the fragments and then drying them;

(4) melting: heating the fragments at high temperature to form a melt;

(5) molding: the melt is injected into an extruder to form a plastic part.

Compared with the prior art, the recyclable composite packaging bag recycling method has the advantages that the recyclable composite packaging bag is thoroughly cleaned and smashed into fragments, and then is heated at high temperature to form a melt to be recycled for secondary manufacturing of plastic parts.

Preferably, in the step (1) and the step (3), the cleaning liquid at 60-70 ℃ is used for cleaning.

Drawings

FIG. 1 is a cross-sectional view of a first embodiment;

FIG. 2 is a view showing the composite packaging material of the first embodiment overlaid on a packaging base box;

FIG. 3 is a schematic view of the second embodiment;

FIG. 4 is a sectional view of the second embodiment.

Description of reference numerals:

1 film body, 2 bag bodies, 3 outer layers, 4 inner layers, 5 bonding layers and 6 containing cavities.

Detailed Description

Embodiments of the present invention are described below with reference to the accompanying drawings:

example one

Referring to fig. 1 to 2, the recyclable composite packaging material of the embodiment is applied to an open cover of an open bottom packaging box for placing food, and comprises a film body 1, wherein the film body 1 is formed by compounding an outer layer 3 and an inner layer 4, the outer layer 3 and the inner layer 4 are both made of at least two materials selected from HDPE, MDPE, LDPE, mPE and vinyl-containing copolymer, and an opening agent and/or a slipping agent is/are added into the outer layer 3 and the inner layer 4.

The outer layer 3 comprises HDPE and LDPE, wherein the weight percentage of the HDPE is 60-90%, and the weight percentage of the LDPE is 10-30%; the inner layer 4 comprises LDPE and mPE, wherein the weight percentage of the LDPE is 40-80%, and the weight percentage of the mPE is 10-50%.

Specifically, mPE contained in the inner layer 4 is LLDPE (linear low density polyethylene); compared with LDPE, LLDPE has excellent strength, toughness, rigidity, heat resistance, cold resistance and acid and alkali resistance, and the addition of LLDPE can improve the cracking resistance, impact resistance and tear resistance of the inner layer 4.

The outer layer 3 mainly comprises HDPE and LDPE, so that the outer layer 3 is ensured to keep good thermoplasticity, and simultaneously, the HDPE has good stiffness, flatness and high temperature resistance compared with other PE materials, so that the attractiveness and usability of the outer layer 3 are improved, the composite packaging material is ensured not to be damaged easily, the composite packaging material is convenient to recycle, and the addition of the LDPE can improve the processability and ensure the quality of secondary regeneration products; the inner layer 4 mainly comprises LDPE and mPE, so that the inner layer 4 has good biocompatibility while keeping good thermoplasticity, can contact food, has good low-temperature heat sealing performance, can be bonded to form a package under low-temperature heating, and reduces production energy consumption.

Specifically, the weight percentage of the opening agent and/or the slipping agent in the outer layer 3 and the inner layer 4 is 1-4%, in this embodiment, the opening agent and the slipping agent are contained in the outer layer 3 and the inner layer 4, and the opening agent and the slipping agent belong to the existing materials and are not the main points of the invention, and are not described in detail herein.

The inner layer 4 contains a copolymer containing vinyl, and the copolymer containing vinyl in the inner layer 4 is POP; the weight percentage of the vinyl-containing copolymer in the inner layer 4 is 10-30%.

By adding POP (vinyl polymer grafted polyether polyol) into the inner layer 4, the elasticity of the inner layer 4 can be improved, so that the inner layer 4 has high bearing capacity and high modulus, and the invasion of bacteria caused by micropores on the surface of the inner layer 4 during pulling is avoided, thereby providing better coating, sealing and fresh-keeping effects for food; in addition, the inner layer 4 mainly composed of LDPE and POP can be subjected to thermoplastic deformation at a lower heating temperature, so that the inner layer 4 can be covered on the surface of the food with a lower (110-120 ℃) heat sealing temperature, or two opposite inner layers 4 can be heat sealed to form a bagged package.

Referring to fig. 1, the outer layer 3 and the inner layer 4 are compounded by an adhesive layer 5, the adhesive layer 5 being formed of an adhesive; the composite packaging material can be formed by compounding the outer layer 3 and the inner layer 4 in a thermal compounding mode, and the compounding temperature of the outer layer 3 and the inner layer 4 during compounding can be reduced by arranging the bonding layer 5, or the composite molding can be realized without a thermal compounding mode, so that the production energy consumption is reduced.

Outer 3, include smooth agent in the inlayer 4, thereby reduce outer 3, the coefficient of friction of the relative one side of inlayer 4, if adopt the thermal compound mode directly with outer 3, inlayer 4 is in the same place, there may be the insecure problem of laminating, through setting up bond line 5, can avoid outer 3, when the relative one side of inlayer 4 is compound, can laminate firmly, and outer 3, include smooth agent in the inlayer 4, can ensure that it and 5 bonding of bond line one side completely isolated air, avoid having the bubble and reduce bonding strength between its and the bond line 5.

Specifically, the thickness of the outer layer 3 is 20 to 40 μm, the thickness of the adhesive layer 5 is 0.5 to 2 μm, and the thickness of the inner layer 4 is 50 to 80 μm.

In the embodiment, the adhesive on the adhesive layer 5 can be POE, the POE has viscosity after being heated, and when the composite packaging material is produced, the outer layer 3, the POE and the inner layer 4 can be compounded through a three-layer co-extruder; or, the adhesive on the adhesive layer 5 can be polyurethane, and because the thickness of the adhesive layer 5 is smaller and the addition amount of the polyurethane adhesive is smaller, the influence on the secondary reconstituted product in the recycling and reconstitution process can be ignored; other types of binders, can be removed during recycling by adding a debonder.

The inner side of the outer layer 3 is subjected to corona treatment and then is compounded with the inner layer 4 to form a film body 1; because the outer layer 3 mainly comprises ethylene materials, the surface of the outer layer 3 is smooth and high, and the ethylene materials are nonpolar substances (the surface tension is low, so that ink/adhesive cannot be firmly attached), the surface energy of the inner side of the outer layer 3 is changed by carrying out corona on the inner side of the outer layer 3, the surface polarity is increased, the firmness degree of the inner side of the outer layer 3 after being bonded with the bonding layer 5 is convenient to improve, and the separation of the outer layer 3 and the inner layer 4 caused by the falling of the bonding layer 5 is avoided.

A printing layer (not shown in the figure) is arranged on the inner side of the outer layer 3, and patterns are printed on the printing layer; outer 3 has carried out corona treatment in advance to 5 one sides in the bond line, behind the printing layer, its printing ink can be stably attached to outer 3 inboards, avoids the printing ink pattern because printing ink pine takes off and the distortion, and in addition, the printing layer is located between outer 3 and the bond line 5, and bond line 5 can provide the bearing effect to the printing layer, further makes the printing layer adhesion at outer 3 inboards to can improve the aesthetic property of composite packaging material, avoid composite packaging material outward appearance too monotonous.

As a modification, the printing ink on the printing layer of the embodiment is a vinyl-containing polymer, specifically a printing ink containing a branched vinyl resin, and the use of the printing ink containing a branched vinyl resin can reduce the introduction of impurities into the composite packaging material, and the printing ink containing a branched vinyl resin is in the prior art, and will not be described in detail here.

The outer side of the outer layer 3 is subjected to corona treatment and then is compounded with the inner layer 4 to form a film body 1; because the ethylene material is a nonpolar substance, the surface polarity of the ethylene material is increased by performing corona on the outer side of the outer layer 3, the high temperature resistance of the outer side surface of the outer layer 3 is improved (improved to 130-.

Surface layer test data

Sample # 1 to 8# ingredient Table

Ingredient tables of samples No. 9 to No. 16

Sample No. 17 to 24# ingredient Table

And (4) testing standard:

a first part:

ASTM D4635-;

ASTM D3981-2003 polyethylene films made of medium density polyethylene for general use and packaging;

GB/T1037-1988 test method for water vapor permeability of plastic films and sheets;

GB/T1038-2000 test method for gas permeability of plastic films and sheets;

GB/T31402-2015 test method for antibacterial property of plastic and plastic surfaces;

ASTM D903-10 test method for peel resistance or peel strength of adhesives.

A second part:

ASTM G-151 Standard test methods for Exposure of non-metallic materials to accelerated test Equipment Using laboratory light sources (ultraviolet radiation Using ultraviolet light aging test Chamber);

GB/T7142-;

GB/T1040-2006 test method for tensile properties of plastics.

By performing performance tests on samples 1# to 40# according to the related first part of test standards, selecting samples with performance meeting the first part of national standards, comparing the same group of samples with different groups of samples, and testing the influence of the addition of the opening agent and the slipping agent on the adhesive effect of the adhesive layer according to ASTM D903-10, screening out samples with relatively superior performance and relatively low production cost, namely samples 6#, 7#, 8#, 14#, 15#, and 16#, screening out samples without the opening agent and the slipping agent, and remaining samples of samples 14#, 15#, and 16#, the following experiment emphasizes performing the performance tests on the durability (after aging according to the second part of test standards) of the samples 14#, 15#, and 16#, wherein the heating aging test temperature is three constant temperature of 50 ℃, 60 ℃ and 70 ℃, the samples after aging at constant temperature of 70 ℃ are selected for performing the performance tests, the following test data are representative data selected after performing a plurality of tests.

Ultraviolet aging test data sheet of specified sample (constant temperature 35 degree)

Conclusion 1: the outer layer material shows an increasing trend of tensile strength and elongation at break along with the increase of the content of HDPE; as the uv irradiation time increases, the tensile strength and elongation at break of HDPE and/or LDPE show an increasing trend; the performance and production costs of samples 15# and 16# were relatively balanced, corresponding to the resulting HDPE, LDPE, opening agent and slip agent contents: 70-90%, 10-30% and 1-2%.

Specified sample heating aging test data table (constant temperature 70 degree)

Conclusion 2: the sample consisting of the HDPE, the LDPE, the opening agent and the slipping agent has good thermal stability, and although the aging tendency appears after the sample is heated at constant temperature for 90 days, the tensile resistance is still good; sample # 31 has relatively balanced performance, production cost, and high recovery feasibility.

Inner layer test data

Sample 1 to 8 ingredient tables

Sample 9 to 16 ingredient tables

Sample 17 to 24 ingredient tables

Sample 25 to 32 ingredient list

Sample 33 to 40 ingredient list

Sample 41 to 48 ingredient list

By performing a performance test on samples 1 to 40 according to the above-mentioned first part of the test standards, selecting samples whose performance meets the first part of the national standards, comparing the samples of the same group and the samples of different groups, and testing the influence of the addition amount of the opening agent and the slip agent on the adhesion effect of the adhesive layer according to ASTM D903-10, screening out samples whose performance is relatively superior and whose production cost is relatively low, and screening out samples which do not contain POP or the opening agent and the slip agent, and leaving samples which are 20, 21, 22, 23, 28, 29, 30, 31, 36, 37, 38, 39, 44, 45, 46, and 47, it is necessary to screen out samples which contain the opening agent and the slip agent and have a higher content of the opening agent and the slip agent but not higher than 4% because the inner layer material has a higher requirement on airtightness and takes biocompatibility into consideration, the remaining test samples were 20, 21, 22, 23, 28, 29, 30, 31, 44, 45, 46 and 47, since the effect of the opening agent and the slip agent is known, only performance tests of 20, 21, 22, 23, 28, 29, 30 and 31 are required, the following experiments focused on the durability (after aging according to the second part of the test standards) of the above samples, but because the light stability of LDPE, LLDPE, POP, the opening agent and the slipping agent is good, the inner layer material is coated by the outer layer material, so that the outer light can be filtered, the aging test of the inner layer material is mainly a heating aging test, the heating aging test temperature is three constant temperatures of 50 ℃, 60 ℃ and 70 ℃, the sample aged at the constant temperature of 70 ℃ is selected for performance test in the embodiment, and the following test data are representative data selected after multiple groups of tests are performed.

Specified sample heating aging test data table (constant temperature 75 degree)

Conclusion 3: the tensile strength and the elongation at break of the inner layer material show an upward trend along with the increase of the content of LLDPE; the samples containing more POPs at normal temperature have better enhanced tensile strength and elongation at break; as the heating time increased, the tensile strength and elongation at break of the sample first showed a downward trend and gradually stabilized.

Summary 1: since the outer layer material and the inner layer material are used after being compounded, it is necessary to select a test group having a tensile strength and an elongation at break close to each other under the same test conditions, and therefore, the composite packaging material of samples 15# and 16# (outer layer material) and sample 30 × (inner layer material) are used in an optimum component ratio.

To summarize 2: according to conclusion 3, in order to ensure the elasticity of the inner layer 4 and thus to make the inner layer 4 have high load-bearing and high modulus, it is necessary to ensure the addition amount of the vinyl group-containing copolymer, and according to the above-mentioned aging test results, the addition amount of the vinyl group-containing copolymer in the inner layer 4 is controlled to 20 ± 5%, and further, since it is necessary to consider recycling processing utilization, the addition of LLDPE increases the difficulty of recycling processing although it can improve the performance of the inner layer material, and therefore, it is conceivable to control the addition amount of LDPE in the inner layer material to 50 ± 10%, the addition amount of LLDPE to 20 ± 10%, and the total addition amount of the opening agent and the slipping agent to 2 ± 1%.

Example two

Referring to fig. 3 to 4, the recyclable composite packaging material of the embodiment comprises a bag body 2, wherein the bag body 2 is formed by compounding the composite packaging material of the first embodiment, and the bag body 2 is provided with a containing cavity 6 with an upper end opened.

Specifically, the bag body 2 may be formed by folding two composite packaging materials and then heat-sealing both sides, or the bag body 2 may be formed by folding two composite packaging materials and then heat-sealing any three sides.

The inner layer 4 contains a slipping agent, the friction coefficient of the opposite side of the inner layer 4 of the bag body 2 is lower, a smooth surface is formed, and the two inner layers 4 can isolate air outside the joint after being tightly contacted, so that the sealing and fresh-keeping effects of the composite packaging material are improved.

Other technical features of the recyclable composite packaging bag of the present embodiment are the same as those of the recyclable composite packaging material of the first embodiment, and will not be described in detail herein.

EXAMPLE III

(3) cleaning: washing the fragments and then drying them;

(4) melting: heating the fragments at high temperature to form a melt;

(5) molding: the melt is injected into an extruder to form a plastic part.

In the step (1), the composite packaging bag is placed in a cleaning pool, and is soaked for 0.5-5 hours by using a cleaning solution at 60 ℃; or putting the composite packaging bag into a cleaning tank, and spraying and washing by using a cleaning solution at 60 ℃; wash the compound wrapping bag of retrieving through using 60 ℃ cleaning solution, can get rid of the great pollutant of area (like the dust on attaching to compound wrapping bag, greasy dirt and printing ink etc.), thereby improve the cleanliness of the compound wrapping bag of retrieving, avoid follow-up carry out compound wrapping bag in the broken many pollutants of time of many mix the piece, and the pollutant adhesion is to the film shredder, influence the crushing effect of film shredder to compound wrapping bag, in addition, it is lower to be less than 60 ℃ cleaning solution getting rid of greasy dirt and printing ink and bactericidal effect, clean effect is thorough inadequately.

In the step (2), a decoloring agent is mixed into the fragments, and the fragments are placed for 2 to 24 hours for decoloring; by decoloring the composite packaging bag, ink printed on the fragments can be removed, so that impurities on the fragments are reduced, and the brightness of the fragments is improved.

In the step (3), the fragments can be cleaned in any one of the following manners:

the first mode is as follows: putting the fragments into a first stirring pool containing 70 ℃ cleaning solution, stirring the water in the first stirring pool, standing for 0.5-5h, and fishing or filtering to recover the fragments.

The second mode is as follows: putting the fragments into a first stirring tank containing 70 ℃ disinfectant, stirring the water in the first stirring tank, standing for 0.5-5h, and fishing or filtering to recover the fragments.

The third mode is as follows: putting the fragments into a first stirring pool containing 70 ℃ cleaning solution, stirring the water in the first stirring pool, standing for 0.5-5h, and fishing or filtering to recover the fragments; putting the fragments into a second stirring tank containing 70 ℃ disinfectant, stirring the water in the second stirring tank, standing for 0.5-5h, and fishing or filtering to recover the fragments.

The fragments are subjected to secondary cleaning, so that tiny pollutants adsorbed on the fragments are removed, impurities (including decolorant added in a decoloring process) on the fragments are further removed, the cleanliness of the fragments is improved, and the quality of a secondarily manufactured product is guaranteed; in addition, compare and wash for the first time and use 60 ℃ cleaning solution, through improving the cleaning solution temperature to 70 ℃, can carry out more thorough cleanness (getting rid of impurity and killing the bacterium) to the piece to improve the cleanliness factor of piece, if use the cleaning solution that is greater than 70 ℃, probably cause the damage to the piece material, and the cleaning solution that is greater than 70 ℃ also can cause the energy extravagant, and also has the potential safety hazard to equipment and production personnel.

As an optimization scheme, in the step (3), after the fragments are cleaned, the fragments are centrifuged or squeezed, so that the water content of the fragments is reduced, the time for drying or drying the fragments in the air is effectively shortened, and in addition, the centrifugation or squeezing can compress the volume of the fragments, so that the production space occupied by the fragments is reduced, and the fragments can be conveniently stored or transferred to equipment where the next process is located.

Preferably, in the step (4), a small amount of the melt is taken for component detection; the components of the recycled melt are detected, so that the products produced by secondary production can keep good performance, and the recycled materials can be recycled to be reproduced into products with higher use requirements.

As an optimized scheme, in the step (4), a whitening agent is added; the chroma of the reclaimed material is improved by adding the whitening agent.

Preferably, in the step (4), the component of the melt is detected and the colorimetric measurement is performed at the same time.

Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. The recyclable composite packaging material is characterized by comprising a film body, wherein the film body is formed by compounding an outer layer and an inner layer, the outer layer and the inner layer are both prepared by mixing at least two materials of HDPE, MDPE, LDPE, mPE and vinyl-containing copolymer, and an opening agent and/or a slipping agent is/are added into the outer layer and the inner layer.

2. The recyclable composite material as claimed in claim 1, wherein the outer layer comprises at least HDPE and LDPE, wherein the weight percentage of HDPE is 60-90%, and the weight percentage of LDPE is 10-30%; the inner layer at least comprises LDPE and mPE, wherein the weight percentage of the LDPE is 40-80%, and the weight percentage of the mPE is 10-50%.

3. The recyclable composite packaging material as claimed in claim 2, wherein the inner layer contains a vinyl-containing copolymer, and the vinyl-containing copolymer in the inner layer is POP.

4. The recyclable composite packaging material of claim 1, wherein the outer layer and the inner layer are compounded by an adhesive layer.

5. The recyclable composite packaging material as claimed in claim 4, wherein the inner side of the outer layer is corona-treated and then combined with the inner layer to form a film body.

6. The recyclable composite packaging material as claimed in claim 5, wherein the outer layer is provided with a printed layer on the inside, and the printed layer is printed with a pattern.

7. The recyclable composite packaging material as claimed in any one of claims 1 to 6, wherein the outer layer is corona-treated and then combined with the inner layer to form a film body.

8. A composite packaging bag characterized by comprising a bag body made of the packaging material according to any one of claims 1 to 7.

9. A recycling method for the composite packing bag according to claim 8, comprising the steps of:

(3) cleaning: washing the fragments and then drying them;

(4) melting: heating the fragments at high temperature to form a melt;

(5) molding: the melt is injected into an extruder to form a plastic part.

10. The recycling method according to claim 9, wherein in the step (1) and the step (3), the washing is performed using a 60-70 ℃ cleaning solution.