WO2022027603A1

WO2022027603A1 - Antibacterial pva/starch biodegradable thin film and preparation method therefor

Info

Publication number: WO2022027603A1
Application number: PCT/CN2020/107847
Authority: WO
Inventors: 陈昌平
Original assignee: 南京五瑞生物降解新材料研究院有限公司
Priority date: 2020-08-07
Filing date: 2020-08-07
Publication date: 2022-02-10
Also published as: AU2020227119A1

Abstract

An antibacterial PVA/starch biodegradable thin film, prepared by the following raw materials in parts by weight: 100 parts of PVA, 50-80 parts of starch, 30-42 parts of a plasticizer, 12-18 parts of PLA, 5-10 parts of a cross-linking modifier, and 3-7 parts of an antibacterial agent. Also disclosed is a preparation method therefor. By means of reasonable raw material proportioning, the prepared thin film has good mechanical properties, air tightness, water resistance, and antibacterial properties, and can be automatically degraded under natural conditions after being discarded, so that the environmental pollution pressure is relieved and the invention can be applied to various occasions.

Description

Antibacterial PVA/starch biodegradable film and preparation method thereof

technical field

The invention relates to an antibacterial PVA/starch biodegradable film and a preparation method thereof, belonging to the field of degradable plastics.

Background technique

In order to protect the environment and reduce pollution, biodegradable materials have become the focus of research in the field of packaging materials. Among them, the PVA/starch mixture has high cost performance and moderate mechanical strength, excellent gas barrier properties to oxygen and nitrogen, and good water solubility, and is currently a research hotspot of biodegradable materials. However, due to the presence of a large number of hydroxyl groups in the side chains of PVA/starch, it has hygroscopicity and extremely poor moisture resistance, which cannot prevent the inner packaging product from being polluted by the external environment, and its use is limited.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an antibacterial PVA/starch biodegradable film with good waterproof performance and antibacterial performance.

The object of the present invention is achieved through the following technical solutions:

An antibacterial PVA/starch biodegradable film is prepared from the following raw materials by weight:

Preferably, 10-20 parts of modified starch are also included, and the modified starch is oxidized starch or hydroxypropyl starch.

Preferably, the crosslinking modifier is an aziridine crosslinking agent.

Preferably, the antibacterial agent is castor oil, eucalyptus oil or cinnamon oil.

The plasticizer is glycerin or epoxidized soybean oil.

The present invention also discloses the preparation method of the above-mentioned antibacterial PVA/starch biodegradable film, and its steps include:

(1) Add the cross-linking modifier and a part of the plasticizer to the PVA, stir at high speed and dry; add the rest of the plasticizer and antibacterial agent to the starch, stir at high speed, dry, put it in the mixer and mix it with two Screw extrusion granulation;

(2), take the PLA granules and the PVA/starch granules of step (1) in proportion, put them into a mixer and mix them, then extrude them with a single screw, and then blow them into a film.

Preferably, in step (1), the stirring speed of PVA is 800rpm, and the time is 25min, the stirring speed of starch is 800rpm, and the time is 20min, the temperature of the twin-screw extrusion is 165 ℃, the rotation speed of the screw is 380r/min, and the pressure of the die head is 5MPa. .

Preferably, in step (2), the extrusion temperature of the single screw is 180°C, the blowing temperature is 210°C, and the film thickness is 0.03 mm.

The present invention adds plasticizer, PLA, crosslinking modifier and antibacterial agent to PVA/starch material. The aziridine cross-linking agent can generate cross-linking, reduce the hydroxyl group of the side chain, and improve the water resistance of the material. The addition of plasticizer can effectively improve the mechanical properties of PVA/starch films. The addition of PLA can reduce the alcoholysis degree of PVA and improve the toughness and waterproof performance of PVA/starch film. Adding antibacterial agents makes the product have good antibacterial properties.

Through the reasonable ratio of raw materials, the film prepared by the invention has good mechanical properties, air tightness, waterproof performance, and antibacterial properties, and after being discarded, it is automatically degraded under natural conditions, reducing the pressure of environmental pollution, and can be applied to many an occasion.

detailed description

Example 1

The antibacterial PVA/starch biodegradable film is prepared from the following raw materials by weight:

Example 2

Example 3

Example 4

The preparation method of embodiment 1-4 is:

(1), add the crosslinking modifier and half of the plasticizer to the PVA, stir at a high speed, the stirring speed is 800rpm, the time is 25min, and dry; add the remaining plasticizers and antibacterial agents to the starch, stir at a high speed, and stir The speed is 800rpm, the time is 20min, dried, put into a mixer and mixed with twin-screw extrusion granulation, the extrusion temperature is 165 ℃, the screw rotation speed is 380r/min, and the die pressure is 5MPa;

(2), take the PLA granules and the PVA/starch granules of step (1) in proportion, put them into the mixer and extrude with a single screw after mixing, the extrusion temperature is 180 ° C, and then blow molding into a film, the blow molding temperature is 210 ℃, the film thickness is 0.03mm.

The performance of the films prepared in Examples 1-4 was tested according to GB/T1040.3-2006, and the performance parameters are shown in Table 1.

Table 1 The film performance testing data of Examples 1-4

The products of Examples 1-4 were subjected to composting experiments, and the results showed that the biodegradation rate after 81 days was >75%.

Claims

An antibacterial PVA/starch biodegradable film is prepared from the following raw materials by weight:
The antibacterial PVA/starch biodegradable film according to claim 1, further comprising 10-20 parts of modified starch, wherein the modified starch is oxidized starch or hydroxypropyl starch.
The antibacterial PVA/starch biodegradable film according to claim 2, wherein the crosslinking modifier is an aziridine crosslinking agent.
The antibacterial PVA/starch biodegradable film according to claim 3, wherein the antibacterial agent is castor oil, eucalyptus oil or cinnamon oil.
The antibacterial PVA/starch biodegradable film according to claim 3, wherein the plasticizer is glycerol or epoxidized soybean oil.
The preparation method of the antibacterial PVA/starch biodegradable film described in any one of claim 1-5, its step comprises:

(1) Add the cross-linking modifier and a part of the plasticizer to the PVA, stir at high speed and dry; add the rest of the plasticizer and antibacterial agent to the starch, stir at high speed, dry, put it in the mixer and mix it with two Screw extrusion granulation;

(2), take the PLA granules and the PVA/starch granules of step (1) in proportion, put them into a mixer and mix them, then extrude them with a single screw, and then blow them into a film.
The preparation method of antibacterial PVA/starch biodegradable film according to claim 6, is characterized in that: in step (1), PVA stirring speed is 800rpm, and the time is 25min, and the starch stirring speed is 800rpm, and the time is 20min. The temperature of screw extrusion was 165°C, the screw rotation speed was 380r/min, and the die pressure was 5MPa.
The method for preparing an antibacterial PVA/starch biodegradable film according to claim 7, characterized in that: in step (2), the single screw extrusion temperature is 180°C, the blowing temperature is 210°C, and the film thickness is 0.03mm .