AU2020227119A1

AU2020227119A1 - Antibacterial PVA/starch biodegradable thin film and preparation method thereof

Info

Publication number: AU2020227119A1
Application number: AU2020227119A
Authority: AU
Inventors: Changping Chen
Original assignee: Nanjing Wurui Biodegradable New Material Research Institute Co Ltd
Current assignee: Nanjing Wurui Biodegradable New Material Research Institute Co Ltd
Priority date: 2020-08-07
Filing date: 2020-08-07
Publication date: 2022-02-24
Also published as: WO2022027603A1

Abstract

The present invention discloses an antibacterial PVA/starch biodegradable thin film which is prepared from 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 crosslinking modifier, and 3-7 parts of an antibacterial agent. The present invention further discloses a preparation method of the antibacterial PVA/starch biodegradable thin film. By reasonably matching the raw materials, the thin film prepared in the present invention has good mechanical performance, airtightness, waterproofness and antibacterial performance, automatically degrades under natural conditions after being abandoned, thereby relieving the environmental pollution pressure, and can adapt to various occasions.

Description

ANTIBACTERIAL PVA/STARCH BIODEGRADABLE THIN FILM AND PREPARATION METHOD THEREOF BACKGROUND

[0001] Technical Field

[0002] The present invention relates to an antibacterial PVA/starch biodegradable thin film and a preparation method thereof, and belongs to the field of degradable plastics.

[0003] Related Art

[0004] In order to protect the environment and reduce pollution, biodegradable materials become a research focus in the field of packaging materials. A PVA/starch mixture is the current research focus due to its high cost performance and moderate mechanical strength, excellent gas barrier property to oxygen, nitrogen and the like, and good water solubility. However, due to a large number of hydroxyl groups in PVA/starch side chains, the PVA/starch mixture has hygroscopicity and extremely poor moisture resistance, and cannot prevent internal packaged products from being contaminated by an external environment, so use is limited.

SUMMARY

[0005] The present invention aims to provide an antibacterial PVA/starch biodegradable thin film which has good waterproofness and antibacterial performance.

[0006] The objective of the invention is achieved through the technical schemes as follows: An antibacterial PVA/starch biodegradable thin film is prepared from 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 crosslinking modifier, and 3-7 parts of an antibacterial agent.

[0007] Preferably, the antibacterial PVA/starch biodegradable thin film further comprises 10-20 parts of modified starch, and the modified starch is oxidized starch or hydroxypropyl starch.

[0008] Preferably, the crosslinking modifier is an aziridine crosslinker.

[0009] Preferably, the antibacterial agent is castor oil, eucalyptus oil or cassia oil.

[0010] The plasticizer is glycerin or epoxidized soybean oil.

[0011] The present invention further discloses a preparation method of the antibacterial PVA/starch biodegradable thin film, and the preparation method comprises the following steps: (1) adding a crosslinking modifier and part of a plasticizer to PVA for stirring at a high speed and drying; adding the remaining plasticizer and an antibacterial agent to starch for stirring at a high speed and drying; and putting the two mixtures into a mixer for mixing, and then performing extruding granulating by twin screws; and (2) taking PLA granules and PVA/starch granules in step (1) in proportion, putting the PLA granules and the PVA/starch granules into a mixer for mixing, then extruding the mixture by a single screw, and then performing blow molding to form a film.

[0012] Preferably, instep (1), a PVA stirring speed is 800 rpm, PVA stirring time is 25 min, a starch stirring speed is 800 rpm, starch stirring time is 20 min, a twin screw extruding temperature is 165°C, a screw rotating speed is 380 r/min, and a die head pressure is 5 MPa.

[0013] Preferably, in step (2), a single screw extruding temperature is 180°C, a blow molding temperature is 210°C, and a film forming thickness is 0.03 mm.

[0014] The plasticizer, the PLA, the crosslinking modifier and the antibacterial agent are added to a PVA/starch material. The aziridine crosslinker can generate crosslinking, reduce side chain hydroxyl groups and improve the waterproofness of the material. By adding the plasticizer, mechanical properties of the PVA/starch thin film can be effectively improved. By adding the PLA, the alcoholysis degree of the PVA can be reduced, and the toughness and waterproofness of the PVA/starch thin film can be improved. By adding the antibacterial agent, the product has good antibacterial performance.

[0015] By reasonably matching the raw materials, the thin film prepared in the present invention has good mechanical performance, airtightness, waterproofness and antibacterial performance, automatically degrades under natural conditions after being abandoned, thereby relieving the environmental pollution pressure, and can adapt to various occasions.

DETAILED DESCRIPTION

[0016] Example 1

[0017] An antibacterial PVA/starch biodegradable thin film is prepared from the following raw materials in parts by weight: 100 parts of PVA, 80 parts of starch,

20 parts of oxidized starch, 42 parts of glycerin, 18 parts of PLA, 10 parts of an aziridine crosslinking modifier, and 3 parts of castor oil.

[0018] Example2

[0019] An antibacterial PVA/starch biodegradable thin film is prepared from the following raw materials in parts by weight: 100 parts of PVA, 50 parts of starch, 15 parts of hydroxypropyl starch, 30 parts of glycerin, 12 parts of PLA, 8 parts of an aziridine crosslinking modifier, and 3 parts of eucalyptus oil.

[0020] Example 3

[0021] An antibacterial PVA/starch biodegradable thin film is prepared from the following raw materials in parts by weight: 100 parts of PVA, 70 parts of starch, 10 parts of oxidized starch, 35 parts of epoxidized soybean oil, 15 parts of PLA, 5 parts of an aziridine crosslinking modifier, and 5 parts of eucalyptus oil.

[0022] Example 4

[0023] An antibacterial PVA/starch biodegradable thin film is prepared from the following raw materials in parts by weight: 100 parts of PVA, 50 parts of starch, 20 parts of hydroxypropyl starch, 35 parts of glycerin, 15 parts of PLA, 8 parts of an aziridine crosslinking modifier, and 7 parts of cassia oil. A preparation method for examples 1-4 comprises the steps: (1) adding the crosslinking modifier and half of the plasticizer to the PVA for stirring at a high speed of 800 rpm for 25 min and drying; adding the remaining plasticizer and the antibacterial agent to the starch for stirring at a high speed of 800 rpm for 20 min and drying; and putting the two mixtures into a mixer for mixing, and then performing extruding granulating by twin screws at an extruding temperature of 165°C, a screw rotating speed of 380 r/min and a die head pressure of 5 MPa; and (2) taking PLA granules and PVA/starch granules in step (1) in proportion, putting the PLA granules and the PVA/starch granules into a mixer for mixing, then extruding the mixture by a single screw at an extruding temperature of 180°C, and then performing blow molding to form a film at a blow molding temperature of 210°C and a film forming thickness of 0.03 mm.

[0024] Properties of the thin films prepared in examples 1-4 are detected according to GB/T 1040.3-2006, and property parameters are shown in table 1.

Table 1 Thin film property detection data of examples 1-4 Example 1 Example 2 Example 3 Example 4 Tensile strength MD 26 34 29 30 (MPa) TD 24 31 26 27 Wet strength tensile MD 21 27 23 24 strength (MPa) TD 20 25 22 23 Tear strength MD 87 99 91 94 (N/15mm) TD 81 90 81 85

[0025] A composting experiment is performed on the products in examples 1-4, and the results show that 81 days later, the biological decomposition rate is larger than 75%.

Claims

1. An antibacterial PVA/starch biodegradable thin film, prepared from 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 crosslinking modifier, and 3-7 parts of an antibacterial agent.

2. The antibacterial PVA/starch biodegradable thin film according to claim 1, further comprising 10-20 parts of modified starch, wherein the modified starch is oxidized starch or hydroxypropyl starch.

3. The antibacterial PVA/starch biodegradable thin film according to claim 2, wherein the crosslinking modifier is an aziridine crosslinker.

4. The antibacterial PVA/starch biodegradable thin film according to claim 3, wherein the antibacterial agent is castor oil, eucalyptus oil or cassia oil.

5. The antibacterial PVA/starch biodegradable thin film according to claim 3, wherein the plasticizer is glycerin or epoxidized soybean oil.

6. A preparation method of the antibacterial PVA/starch biodegradable thin film according to any one of claims 1-5, comprising the following steps: (1) adding a crosslinking modifier and part of a plasticizer to PVA for stirring at a high speed and drying; adding the remaining plasticizer and an antibacterial agent to starch for stirring at a high speed and drying; and putting the two mixtures into a mixer for mixing, and then performing extruding granulating by twin screws; and (2) taking PLA granules and PVA/starch granules in step (1) in proportion, putting the PLA granules and the PVA/starch granules into a mixer for mixing, then extruding the mixture by a single screw, and then performing blow molding to form a film.

7. The preparation method of the antibacterial PVA/starch biodegradable thin film according to claim 6, wherein in step (1), a PVA stirring speed is 800 rpm, PVA stirring time is 25 min, a starch stirring speed is 800 rpm, starch stirring time is 20 min, a twin screw extruding temperature is 165°C, a screw rotating speed is 380 r/min, and a die head pressure is 5 MPa.

8. The preparation method of the antibacterial PVA/starch biodegradable thin film according to claim 7, wherein in step (2), a single screw extruding temperature is 180°C, a blow molding temperature is 210°C, and a film forming thickness is 0.03 mm.