PBAT packaging film with antibacterial function

Abstract

The invention discloses a manufacturing method of a PBAT packaging film with an antibacterial function. The PBAT is high-molecular plastic, and compared with common plastic, the PBAT has good biodegradability and is beneficial to environmental protection. The PBAT can be used for preparing various plastic products such as packaging films. The preservative sorbic acid, benzoic acid and nipagin ester are added into the PBAT material, and the packaging film with certain antibacterial property is prepared by using a solvent evaporation method. The preparation method comprises the following steps: dissolving PBAT plastic in a solvent glacial acetic acid which is nontoxic and easy to neutralize and recover, adding a preservative and a plasticizer, and volatilizing the solvent at a certain temperature. The method overcomes the defects that in the previous plastic production process, a solvent in a solvent volatilization method has toxicity, and a preservative is damaged by high temperature in a blow molding method, the production mode is simple and convenient, and certain practical value is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of packaging film, in particular to a PBAT packaging film with antibacterial function. BACKGROUND

[0002] PBAT (Polybutylene adipate terephthalate) is a synthetic polymer material with biodegradable properties, which is prepared by polycondensation reaction of petroleum-based monomers adipic acid (AA), terephthalic acid (PTA) and 1,4-butanediol (BDO). Its molecular chain contains both aliphatic polyester (polybutylene adipate, PBA) and aromatic polyester (polybutylene terephthalate, PBT) structural units. This unique chemical composition makes it have both mechanical properties and degradable characteristics of traditional plastics, and it has become one of the important environmental protection materials to replace traditional non-degradable plastics. The characteristics of PBAT plastic include:

[0003] 1. Biodegradability

[0004] PBAT can be decomposed into water, carbon dioxide and humus under certain conditions (such as high temperature, high humidity and microbial action in industrial composting environment), and the degradation period is usually 3-6 months. Its degradation mechanism includes hydrolysis and microbial enzyme hydrolysis, and the final product is harmless to the environment, which meets international standards.

[0005] 2. Mechanical properties

[0006] PBAT has excellent flexibility, ductility and impact resistance, close to low-density polyethylene (LDPE), and is suitable for scenarios that require high toughness, such as thin film products.

[0007] 3. Processing adaptability

[0008] It can be produced by conventional plastic processing technologies such as blown film, injection molding and extrusion. When blended with starch, PLA (polylactic acid) and other bio-based materials, it can improve the performance of composite materials and expand the application range.

[0009] Its main application fields are packaging materials, such as supermarket shopping bags, express packaging films, food preservation films, etc., which can replace traditional PE film; disposable products, such as tableware, straws, garbage bags, etc., which meet the demand of "ban on plastic". In addition, it also has wide application in the fields of agriculture and medicine. PBAT plastic has the advantages of reducing environmental pollution, being compatible with existing plastic industry system, and having low industrialization barriers. With the promotion of "ban on plastic", the market demand for PBAT continues to grow, and it has broad development prospects.

[0010] Preservatives are substances that can prevent spoilage and deterioration caused by microorganisms. Common preservatives include sorbic acid, benzoic acid, and propyl gallate.

[0011] 1. Sorbic Acid

[0012] Sorbic acid is a broad-spectrum bacteriostatic agent, which has significant inhibitory effect on mold, yeast and aerobic bacteria. Its mechanism of action is to destroy the enzyme system of microorganisms and inhibit cell respiration.

[0013] 2. Benzoic Acid

[0014] Benzoic acid exerts a preservative effect by inhibiting enzyme activity in microbial cells, which is effective against bacteria and mold, but weak against yeast.

[0015] 3. Parabens (p-hydroxybenzoic acid esters)

[0016] Parabens are a class of broad-spectrum bacteriostatic agents, which are effective against bacteria, mold and yeast, especially gram-positive bacteria. Its mechanism of action is to destroy the cell membrane structure and interfere with energy metabolism. SUMMARY

[0017] The conventional method for preparing plastic film includes blow molding and volatile solvent method. However, it is not easy to uniformly add preservatives by blow molding, and even if it can be added, the high temperature in the production process will destroy the preservatives, so that the preservatives cannot exert their efficacy. The solvents used in the conventional volatile solvent method are mostly expensive and toxic substances, which cannot guarantee safety.

[0018] The present application improves this by using non-toxic and relatively inexpensive solvent - acetic acid to co-dissolve plastic and preservatives, and evaporating acetic acid to prepare PBAT plastic film with added preservatives, so that it has certain bacteriostatic performance and can be used for preservation. The evaporated acetic acid can be absorbed by alkaline substances such as sodium carbonate, without polluting the environment.

[0019] The preservatives used in the present application are sorbic acid, benzoic acid and parabens, which are all allowed substances in the national standard. At the same time, the selected preservatives have the characteristics of low water solubility, which will not cause serious reduction of the barrier properties of plastic film. The process of preparing plastic film in the present application is relatively simple, and the plastic film prepared has certain mechanical strength, so it has certain practicality. At the same time, the biodegradability of PBAT plastic makes it environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The sample of the plastic film prepared in the present application is shown. DETAILED DESCRIPTION

[0021] 1. Measure 100 ml of glacial acetic acid, weigh 6 g of PBAT plastic particles and add them to the bottle, seal and stir. Set the water bath temperature to 90°C, place the sealed bottle in it and continuously stir until the plastic is completely dissolved. Then remove and reserve.

[0022] 2. When in use, place the condensed plastic acetic acid solution in a 50°C water bath to make it liquid again. Add 25-50 μL of plasticizer epoxidized soybean oil, then add 5-10 mg of preservative, and mix until dissolved. The preservative used is one of sorbic acid, benzoic acid or nipagin ester.

[0023] 3. Pour the mixed film solution into the mold while it is hot. In a well-ventilated environment, heat the oven with anti-corrosion properties to 70°C. Place the mold in the oven while surrounding the mold with windproof barriers to prevent hot air from blowing directly onto the film solution. After the acetic acid has completely evaporated, the PBAT plastic film containing the preservative is obtained.

[0024] In actual application, there may be slight differences due to differences in materials, production conditions, etc.

Claims

1. A PBAT packaging film with antibacterial function is a packaging film made of PBAT plastic, produced by a solvent volatilization method, and added with preservatives and plasticizers.

2. The packaging film of claim 1 , wherein the main material is PBAT plastic (polybutylene adipate / terephthalate); the preservative is one of benzoic acid, sorbic acid, and paraben; the plasticizer is epoxidized soybean oil; and the solvent is glacial acetic acid.

3. The method for making the packaging film according to claim 1 comprises the following steps: 1) Take 100ml of glacial acetic acid, weigh 6g of PBAT plastic particles and add them into it. Place the mixture in a sealed mixing bottle and seal with a lid. Set the water bath to 90°C, place the sealed bottle in the water bath, and stir continuously until the plastic is completely dissolved. Remove and set aside. 2) When using, place the condensed acetic acid-plastic in a 50°C water bath to reliquify it. Add 25-50 μL of plasticizer and then 5-10 mg of preservative and dissolve. 3) Pour the hot mixed film solution into the mold. In a well-ventilated environment, heat a corrosion-resistant oven to 70°C. Place the mold in the oven, surrounding it with windproof enclosures to prevent hot air from directly reaching the film solution. Once the acetic acid has completely evaporated, the preservative-containing PBAT plastic film is obtained.

4. The manufacturing method as described in claim 3 may be appropriately adjusted according to actual circumstances.

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