Environment-friendly plastic packaging bag based on PBAT and preparation method of environment-friendly plastic packaging bag

Abstract

The invention relates to the technical field of packaging materials, and discloses a PBAT-based environment-friendly plastic packaging bag and a preparation method thereof.The PBAT-based environment-friendly plastic packaging bag is prepared by taking PBAT as a base material and corn starch, polylactic acid, a linen fiber modified material and the like as auxiliary materials through the processes of mixing, extrusion granulation and film blowing; wherein the linen fiber modified material is linen fiber of which the surface is modified with an active macromolecular antibacterial agent, and due to the existence of the active macromolecular antibacterial agent, a transition layer can be formed between the linen fiber and a PBAT matrix, so that the linen fiber is firmly clamped in the PBAT matrix, and further, the enhanced modification effect of the linen fiber is efficiently exerted, and the mechanical strength of the plastic packaging bag is improved. Besides, the structure of the active macromolecular antibacterial agent contains abundant natural antibacterial agent quercetin, and the plastic packaging bag can be endowed with excellent antibacterial performance, so that the PBAT plastic packaging bag has excellent comprehensive performance, and the application range of the PBAT plastic packaging bag is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging materials, and in particular to an environmentally friendly plastic packaging bag based on PBAT and a preparation method thereof. Background Art

[0002] As an indispensable part of modern life, plastic packaging bags are widely used in food packaging, daily necessities, industrial production and other fields due to their lightness, durability and high cost-effectiveness. However, with the extensive use and improper disposal of plastic products, the problem of plastic pollution has become increasingly serious, causing tremendous pressure on the ecological environment. In order to meet this challenge, environmentally friendly plastic packaging bags have emerged. Among them, PBAT (polybutylene adipate / terephthalate) is a new type of biodegradable material with good flexibility, stretchability and thermal stability. It is gradually used in the field of plastic packaging bags. Its most notable feature is that it can be decomposed by microorganisms under various environmental conditions, such as soil, seawater and compost, and finally completely converted into harmless carbon dioxide and water. This feature makes PBAT have great potential in reducing plastic pollution and protecting the ecological environment.

[0003] However, PBAT also has obvious problems as a base material for plastic packaging bags. On the one hand, its antibacterial properties are poor and cannot meet the needs of food packaging bags. On the other hand, its mechanical strength is gradually unable to meet industry needs. Therefore, enhancing and modifying PBAT is of great significance for its application in the field of plastic packaging bags.

[0004] At present, it is common to improve the functionality of polymer materials by adding modifications. For example, antibacterial properties of materials are enhanced by adding antibacterial agents such as silver, and mechanical strength of materials is enhanced by adding nanomaterials. However, inorganic antibacterial agents such as silver are generally heavy metals, which will cause certain environmental pollution after abandonment. There are obvious interface problems between nanomaterials and PBAT, making it difficult to efficiently exert their advantages. Therefore, the present invention provides an environmentally friendly plastic packaging bag based on PBAT, which can solve the problems in the prior art. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies of the prior art, the present invention provides an environmentally friendly plastic packaging bag based on PBAT and a preparation method thereof.

[0007] (II) Technical solution

[0008] A method for preparing an environmentally friendly plastic packaging bag based on PBAT, wherein the plastic packaging bag is made of the following raw materials in parts by weight:

[0009]

[0010] The preparation method is as follows:

[0011] Step 1: weigh and prepare each raw material according to its weight;

[0012] Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then flax fiber modified material, inorganic filler, lubricant and antioxidant are added to the mixer, the speed is set to 800-1000r / min, and after mechanical stirring and mixing, the mixture is fed into a twin-screw extruder, and a masterbatch is formed through a melt extrusion process;

[0013] Step 3: Place the masterbatch in a film blowing machine, blow the film, and roll up the formed film to obtain a plastic packaging bag.

[0014] As a further embodiment of the present invention, the preparation method of the modified flax fiber material is as follows:

[0015] Step S1, immersing flax fiber in a sodium hydroxide aqueous solution, stirring at a temperature of 60-65° C. for 1-2 hours, separating fiber material, washing and drying, and obtaining functionalized flax fiber;

[0016] Step S2, dispersing the functionalized flax fiber in tetrahydrofuran, then adding an anhydride modifier to the formed dispersion, stirring at room temperature for 2-4 hours, separating the fiber material, and obtaining the modified flax fiber;

[0017] Step S3, ultrasonically dispersing the modified flax fiber in N,N-dimethylformamide, and then adding the active macromolecular antibacterial agent and p-toluenesulfonic acid to the formed uniform dispersion. After the addition, gradually raising the temperature to 90-100° C., stirring is maintained at this temperature for 4-8 hours, and then the temperature is lowered and the material is discharged to separate the fiber product, thereby obtaining a flax fiber modified material.

[0018] As a further solution of the present invention, in step S1, the mass fraction of the sodium hydroxide aqueous solution is 10-20%.

[0019] As a further embodiment of the present invention, in step S2, the acid anhydride modifier is any one of maleic anhydride, succinic anhydride or glutaric anhydride.

[0020] As a further solution of the present invention, in step S3, the specific preparation method of the active macromolecular antibacterial agent is as follows:

[0021] Step SS1, adding quercetin to acetone, stirring mechanically to obtain uniform mixture, placing the mixture in an ice bath, and then adding 2,3-dibromopropionyl chloride. After the addition is complete, removing the mixture from the ice bath, stirring the mixture at room temperature for 2-4 hours, evaporating the solvent, and collecting the product to obtain a quercetin derivative;

[0022] Step SS2, adding the quercetin derivative and the alkyl diamine compound to N, N-dimethylformamide, starting stirring after the addition, and after complete dissolution to form a uniform reaction solution, passing nitrogen protection, raising the temperature to 70-80°C, continuing stirring for 8-12 hours, separating the solid product, and obtaining an active macromolecular antibacterial agent.

[0023] As a further embodiment of the present invention, in step SS1, the molar ratio of quercetin to 2,3-dibromopropionyl chloride is 1:1.

[0024] As a further embodiment of the present invention, in step SS2, the molar ratio of the quercetin derivative to the alkyl diamine compound is 1:1; the alkyl diamine compound is any one of 1,8-octanediamine, decanediamine or 1,12-diaminododecane.

[0025] As a further embodiment of the present invention, in step SS2, the molar ratio of the quercetin derivative to the alkyl diamine compound is 0.8-1:1.

[0026] In the above technical scheme, 2,3-dibromopropionyl chloride and quercetin are first used as reactants, and the active acyl chloride groups and phenolic hydroxyl groups in each other's structures are used for condensation to obtain a quercetin derivative containing two equivalents of halogen substituents in the structure. Then, an alkyl diamine compound is used as a chain extender to carry out a continuous and uninterrupted substitution reaction with the halogen substituents in the structure of the quercetin derivative, thereby obtaining an active macromolecular antibacterial agent with an alternating structure.

[0027] Then, since the surface of the flax fiber treated with alkali and modified with acid anhydride contains active carboxyl substituents, it can undergo amidation reaction with the amino substituents at the end of the active macromolecular antibacterial agent structure under the catalytic action of p-toluenesulfonic acid, thereby modifying the active macromolecular antibacterial agent on the surface of the flax fiber to obtain a flax fiber modified material.

[0028] As a further solution of the present invention, the inorganic filler is any one of talcum powder, calcium carbonate or titanium dioxide; the lubricant is polyethylene wax or paraffin; and the antioxidant is antioxidant 1076 or antioxidant 1010.

[0029] A PBAT-based environmentally friendly plastic packaging bag is prepared using the above-mentioned preparation method.

[0030] (III) Beneficial technical effects

[0031] The present invention obtains a flax fiber modified material by modifying the surface of flax fiber with an active macromolecular antibacterial agent. First, since the active macromolecular antibacterial agent is an organic connection structure, it can form a transition layer between the flax fiber and the PBAT matrix, so that the interface bonding between the flax fiber and the PBAT is greatly enhanced. In addition, during the melt extrusion process, the active macromolecular antibacterial agent will generate intermolecular forces with the PBAT molecular chain, so that the flax fiber is firmly "stuck" in the PBAT matrix, thereby efficiently exerting its own enhancement and modification effect and improving the mechanical strength of the plastic packaging bag. In addition, the active macromolecular antibacterial agent structure contains rich natural antibacterial agent quercetin, which can give the plastic packaging bag excellent antibacterial properties, so that the PBAT plastic packaging bag has excellent comprehensive performance, which is conducive to broadening its application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0033] Figure 1 This is the infrared analysis test diagram of the active macromolecular antibacterial agent. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. Preferred embodiments of the present invention are given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0035] Preparation Example 1

[0036] Preparation of flax fiber modified material:

[0037] Step S1, immersing 10 g of flax fiber in 200 mL of a 20% by mass sodium hydroxide aqueous solution, stirring at 60° C. for 2 h, separating the fiber material, washing and drying, and obtaining functionalized flax fiber;

[0038] Step S2, dispersing 2.4 g of functionalized flax fiber in tetrahydrofuran, and then adding 5 g of succinic anhydride to the formed dispersion, stirring at room temperature for 3 h after the addition, separating the fiber material, and thus obtaining modified flax fiber;

[0039] Step S3, ultrasonically dispersing 1.8 g of modified flax fiber in N,N-dimethylformamide, and then adding 2.5 g of active macromolecular antibacterial agent and 0.1 g of p-toluenesulfonic acid to the formed uniform dispersion. After the addition, gradually raising the temperature to 100° C., stirring is maintained at this temperature for 6 hours, and then the temperature is lowered and the material is discharged to separate the fiber product, thereby obtaining a modified flax fiber material.

[0040] The preparation method of the active macromolecular antibacterial agent is as follows:

[0041] Step SS1, adding 0.4 g of quercetin to acetone, stirring mechanically and placing in an ice bath, then adding 0.33 g of 2,3-dibromopropionyl chloride, removing from the ice bath, stirring at room temperature for 3 h, evaporating to remove the solvent, collecting the product, and obtaining a quercetin derivative;

[0042] Step SS2, add 0.3 g of quercetin derivative and 0.1 g of 1,8-octanediamine to N,N-dimethylformamide, start stirring, and after complete dissolution to form a uniform reaction liquid, pass nitrogen protection, raise the temperature to 75°C, continue stirring for 9 hours, separate the solid product, and the active macromolecular antibacterial agent can be obtained.

[0043] Figure 1 This is the infrared analysis test diagram of the active macromolecular antibacterial agent, where 3405cm -1 and 3379cm -1 The characteristic absorption peak at 3298 cm is the NH characteristic absorption peak in the primary and secondary amine groups. -1 The characteristic absorption peak at 1753 cm is the characteristic absorption peak of phenolic hydroxyl in the quercetin structure. -1 The characteristic absorption peak at 1728 cm is the characteristic absorption peak of the ester group C=O produced by esterification condensation. -1 The characteristic absorption peak that appears at is the characteristic absorption peak of the carbonyl C=O in the quercetin structure.

[0044] Example 1

[0045] A PBAT-based environmentally friendly plastic packaging bag is made of the following raw materials in parts by weight:

[0046]

[0047] The preparation method of the plastic packaging bag is as follows:

[0048] Step 1: weigh and prepare each raw material according to its weight;

[0049] Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then flax fiber modified material, talcum powder, polyethylene wax and antioxidant 1010 are added to the mixer, the speed is set to 800r / min, and the mixture is mechanically stirred and mixed before feeding into a twin-screw extruder. The extruder temperature is controlled to 165°C, and a masterbatch is formed through a melt extrusion process;

[0050] Step 3: Place the masterbatch in a film blowing machine and blow the film to control the thickness to 0.1 mm. Roll up the formed film to obtain a plastic packaging bag.

[0051] The preparation method of the modified flax fiber material is shown in Preparation Example 1, and the same is true for the following.

[0052] Example 2

[0053] A PBAT-based environmentally friendly plastic packaging bag is made of the following raw materials in parts by weight:

[0054]

[0055] The preparation method of the plastic packaging bag is as follows:

[0056] Step 1: weigh and prepare each raw material according to its weight;

[0057] Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then flax fiber modified material, calcium carbonate, polyethylene wax and antioxidant 1076 are added to the mixer, the speed is set to 1000r / min, and the mixture is mechanically stirred and mixed before feeding into a twin-screw extruder. The extruder temperature is controlled to 165°C, and a masterbatch is formed through a melt extrusion process;

[0058] Step 3: Place the masterbatch in a film blowing machine and blow the film to control the thickness to 0.1 mm. Roll up the formed film to obtain a plastic packaging bag.

[0059] Example 3

[0060] A PBAT-based environmentally friendly plastic packaging bag is made of the following raw materials in parts by weight:

[0061]

[0062] The preparation method of the plastic packaging bag is as follows:

[0063] Step 1: weigh and prepare each raw material according to its weight;

[0064] Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then flax fiber modified material, titanium dioxide, paraffin and antioxidant 1010 are added to the mixer, the speed is set to 1000r / min, and the mixture is mechanically stirred and mixed before feeding into a twin-screw extruder, and the extruder temperature is controlled to 165°C, and a masterbatch is formed through a melt extrusion process;

[0065] Step 3: Place the masterbatch in a film blowing machine and blow the film to control the thickness to 0.1 mm. Roll up the formed film to obtain a plastic packaging bag.

[0066] Comparative Example 1

[0067] A PBAT-based environmentally friendly plastic packaging bag is made of the following raw materials in parts by weight:

[0068]

[0069]

[0070] The preparation method of the plastic packaging bag is as follows:

[0071] Step 1: weigh and prepare each raw material according to its weight;

[0072] Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then flax fiber, calcium carbonate, polyethylene wax and antioxidant 1076 are added to the mixer, the speed is set to 1000r / min, and the mixture is mechanically stirred and mixed, and then fed into a twin-screw extruder, and the extruder temperature is controlled to 165°C, and a masterbatch is formed through a melt extrusion process;

[0073] Step 3: Place the masterbatch in a film blowing machine and blow the film to control the thickness to 0.1 mm. Roll up the formed film to obtain a plastic packaging bag.

[0074] Comparative Example 2

[0075] A PBAT-based environmentally friendly plastic packaging bag is made of the following raw materials in parts by weight:

[0076]

[0077] The preparation method of the plastic packaging bag is as follows:

[0078] Step 1: weigh and prepare each raw material according to its weight;

[0079] Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then active macromolecular antibacterial agent, calcium carbonate, polyethylene wax and antioxidant 1076 are added to the mixer, the speed is set to 1000r / min, mechanically stirred and mixed, and then fed into a twin-screw extruder, the extruder temperature is controlled to 165°C, and a masterbatch is formed through a melt extrusion process;

[0080] Step 3: Place the masterbatch in a film blowing machine and blow the film to control the thickness to 0.1 mm. Roll up the formed film to obtain a plastic packaging bag.

[0081] The preparation method of the active macromolecular antibacterial agent is shown in Preparation Example 1.

[0082] Comparative Example 3

[0083] A PBAT-based environmentally friendly plastic packaging bag is made of the following raw materials in parts by weight:

[0084]

[0085] The preparation method of the plastic packaging bag is as follows:

[0086] Step 1: weigh and prepare each raw material according to its weight;

[0087] Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then calcium carbonate, polyethylene wax and antioxidant 1076 are added to the mixer, the speed is set to 1000r / min, and the mixture is mechanically stirred and mixed, and then fed into a twin-screw extruder, and the extruder temperature is controlled to 165°C, and a masterbatch is formed through a melt extrusion process;

[0088] Step 3: Place the masterbatch in a film blowing machine and blow the film to control the thickness to 0.1 mm. Roll up the formed film to obtain a plastic packaging bag.

[0089] Test Case

[0090] The plastic packaging bags in the embodiments and comparative examples were made into single-layer film test samples that met the specifications, and various performance tests were performed. The results are recorded in the following table:

[0091]

[0092]

[0093] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing an environmentally friendly plastic packaging bag based on PBAT, characterized in that: The plastic packaging bag is made of the following raw materials in parts by weight: The preparation method is as follows: Step 1: weigh and prepare each raw material according to its weight; Step 2: PBAT, polylactic acid and corn starch are vacuum dried and then added to a mixer, and then flax fiber modified material, inorganic filler, lubricant and antioxidant are added to the mixer, the speed is set to 800-1000r / min, and after mechanical stirring and mixing, the mixture is fed into a twin-screw extruder, and a masterbatch is formed through a melt extrusion process; Step 3: Place the masterbatch in a film blowing machine, blow the film, and roll up the formed film to obtain a plastic packaging bag.

2. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 1, characterized in that: The preparation method of the flax fiber modified material is as follows: Step S1, using a sodium hydroxide aqueous solution to perform an alkalization treatment on flax fibers to obtain functionalized flax fibers; Step S2, using an anhydride modifier to perform surface modification on the functionalized flax fiber to obtain modified flax fiber; Step S3: using an active macromolecular antibacterial agent, under the catalytic action of p-toluenesulfonic acid, further surface-modify the modified flax fiber to obtain a modified flax fiber material.

3. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 2, characterized in that: In step S1, the mass fraction of the sodium hydroxide aqueous solution is 10-20%.

4. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 2, characterized in that: In step S2, the acid anhydride modifier is any one of maleic anhydride, succinic anhydride or glutaric anhydride.

5. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 2, characterized in that: In step S3, the specific preparation method of the active macromolecular antibacterial agent is as follows: Step SS1, adding quercetin to acetone, stirring mechanically to obtain uniform mixture, placing the mixture in an ice bath, and then adding 2,3-dibromopropionyl chloride. After the addition is complete, removing the mixture from the ice bath, stirring the mixture at room temperature for 2-4 hours, evaporating the solvent, and collecting the product to obtain a quercetin derivative; Step SS2, adding the quercetin derivative and the alkyl diamine compound to N, N-dimethylformamide, starting stirring after the addition, and after complete dissolution to form a uniform reaction solution, passing nitrogen protection, raising the temperature to 70-80°C, continuing stirring for 8-12 hours, separating the solid product, and obtaining an active macromolecular antibacterial agent.

6. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 5, characterized in that: In step SS1, the molar ratio of quercetin to 2,3-dibromopropionyl chloride is 1:

1.

7. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 5, characterized in that: In step SS2, the molar ratio of the quercetin derivative to the alkyl diamine compound is 1:1; the alkyl diamine compound is any one of 1,8-octanediamine, decanediamine or 1,12-diaminododecane.

8. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 5, characterized in that: In step SS2, the molar ratio of the quercetin derivative to the alkyl diamine compound is 0.8-1:

1.

9. The method for preparing an environmentally friendly plastic packaging bag based on PBAT according to claim 1, characterized in that: The inorganic filler is any one of talcum powder, calcium carbonate or titanium dioxide; the lubricant is polyethylene wax or paraffin; and the antioxidant is antioxidant 1076 or antioxidant 1010.

10. An environmentally friendly plastic packaging bag based on PBAT, characterized in that: The method is prepared according to claim 1.

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