A biodegradable polyethylene breathable film and a method for preparing the same

Abstract

The application belongs to the field of high polymer packaging materials and sanitary materials, and particularly relates to a biodegradable polyethylene breathable film and a preparation method thereof. The biodegradable polyethylene breathable film comprises a PE base material and a degradation master batch. The degradation master batch comprises the following raw materials in parts by weight: 70 parts of polypropylene, 20 parts of polycaprolactone, 5-8 parts of maleic anhydride grafted polypropylene, 0.3-0.5 parts of stearic acid amine, 0.1-0.3 parts of erucic acid amide, and 0.1-1.0 parts of stearic acid. The biodegradable polyethylene breathable film prepared by the application is significantly superior to conventional PE films and existing degradable PE film products in degradation performance, and achieves the expected technical target.

Description

Technical Field

[0001] This invention relates to the field of polymer packaging materials and sanitary materials, and in particular to a biodegradable polyethylene breathable membrane and its preparation method. Background Technology

[0002] Polyethylene (PE) breathable membranes are widely used in the packaging and hygiene materials industry due to their advantages such as high production efficiency, strong environmental adaptability and low cost. However, traditional polyethylene (PE) breathable membranes are difficult to biodegrade in the natural environment, and long-term accumulation causes serious "white pollution" problems. Based on this, we propose a biodegradable polyethylene breathable membrane and its preparation method. Summary of the Invention

[0003] This invention proposes a biodegradable polyethylene breathable membrane and its preparation method to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A biodegradable polyethylene breathable membrane includes a PE substrate and a degradation masterbatch, wherein the degradation masterbatch comprises the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 5-8 parts maleic anhydride-grafted polypropylene, 0.3-0.5 parts stearic acid amine, 0.1-0.3 parts erucamide and 0.1-1.0 parts stearic acid.

[0005] Preferably, the degradation masterbatch comprises the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 5 parts maleic anhydride-grafted polypropylene, 0.5 parts stearic acid amine, 0.3 parts erucamide and 1.0 parts stearic acid.

[0006] Preferably, the degradation masterbatch comprises the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 6.5 parts maleic anhydride-grafted polypropylene, 0.4 parts stearic acid amine, 0.2 parts erucamide and 0.5 parts stearic acid.

[0007] Preferably, the degradation masterbatch comprises the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 8 parts maleic anhydride-grafted polypropylene, 0.3 parts stearic acid amine, 0.1 parts erucamide and 0.1 parts stearic acid.

[0008] This invention also proposes a method for preparing a biodegradable polyethylene breathable membrane, comprising the following steps: S1: The polycaprolactone is drawn into the drying drum for drying treatment, thereby removing trace amounts of moisture from the polycaprolactone and setting it aside for later use. S2: Polypropylene, maleic anhydride-grafted polypropylene, stearic acid amine, erucamide, stearic acid and polycaprolactone obtained in S1 are mixed in a closed mixer for 5-10 minutes and then fed into a twin-screw extruder. S3: The twin-screw extruder melts the material at a temperature of 150-160℃. The material extruded from the twin-screw extruder is then cut into particles by a pelletizer, dried by a dewatering machine, and degraded by a vibrating screen to remove defective products, thus obtaining degraded masterbatch. S4: Dry the PE substrate at 80-90℃ for 2-3 hours to obtain a PE substrate with moisture removed; S5: Dry the degradation masterbatch from S3 at 50-60℃ for 2-3 hours to obtain the dehydrated degradation masterbatch. S6: Add the PE substrate obtained in S4 and the degradation masterbatch obtained in S5 into the mixer at a ratio of 99:1 and mix for 5 minutes to obtain the mixed raw material; S7: The mixed raw material obtained in S6 is fed into the corresponding extruder, and the extruder achieves the melting and plasticization of the raw material through the shearing action of the screw. S8: The molten material in the extruder enters the die head through the distributor of the extruder, and is then extruded through the die head to obtain a film material; S9: The membrane material obtained in S8 is rapidly cooled and shaped using a steel roller cooling method; S10: The shaped membrane material is fed into a stretching machine, wherein the longitudinal stretching ratio of the stretching machine is 1.5-2.1 times, and the stretching temperature of the stretching machine is 80-90℃. S11: After being stretched, the membrane material is wound up at room temperature by a traction machine at a winding speed of 80m / min to obtain the finished biodegradable polyethylene breathable membrane.

[0009] Preferably, in step S1, the drying temperature is set to 40-50℃ and the drying time is set to 2-4 hours.

[0010] Preferably, in step S7, the extrusion temperature of the extruder is set to 220-225°C.

[0011] Preferably, in step S8, the temperature of the die head is controlled at 220-230°C, and the thickness of the film material is adjusted by the die head gap.

[0012] Preferably, in step S9, the cooling water temperature for the steel roller cooling method is set to 20-25℃.

[0013] Compared with existing technologies, the biodegradable polyethylene breathable membrane prepared by this invention has significantly better degradation performance than traditional PE membranes and existing degradable PE membrane products, achieving the expected technical goals. Attached Figure Description

[0014] Figure 1 This is a process flow diagram of a method for preparing a biodegradable polyethylene breathable membrane proposed in this invention; Figure 2for Figure 1 The process flow diagram for preparing degradation masterbatch. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example

[0016] This embodiment proposes a biodegradable polyethylene breathable membrane, comprising a PE substrate and a degradation masterbatch. The degradation masterbatch contains the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 5 parts maleic anhydride-grafted polypropylene, 0.5 parts stearic acid amine, 0.3 parts erucamide, and 1.0 part stearic acid.

[0017] Reference Figure 1-2 This embodiment also proposes a method for preparing a biodegradable polyethylene breathable membrane, including the following steps: S1: The polycaprolactone is drawn into a drying chamber for drying. The drying temperature is set to 40℃ and the drying time is set to 4h, thereby removing trace amounts of moisture from the polycaprolactone for later use. S2: Polypropylene, maleic anhydride-grafted polypropylene, stearic acid amine, erucamide, stearic acid and polycaprolactone obtained in S1 are mixed in a closed mixer for 5 minutes and then fed into a twin-screw extruder. S3: The twin-screw extruder melts the material at a temperature of 160°C. The material extruded from the twin-screw extruder is then cut into particles by a pelletizer, dried by a dewatering machine, and degraded by a vibrating screen to remove defective products, thus obtaining degraded masterbatch. S4: Dry the PE substrate at 80°C for 3 hours to obtain a PE substrate with moisture removed; S5: The degradation masterbatch in S3 is dried at 50°C for 3 hours to obtain the dehydrated degradation masterbatch. S6: Add the PE substrate obtained in S4 and the degradation masterbatch obtained in S5 into the mixer at a ratio of 99:1 and mix for 5 minutes to obtain the mixed raw material; S7: The mixed raw material obtained in S6 is fed into the corresponding extruder. The extruder melts and plasticizes the raw material through the shearing action of the screw. The extruder is set to an extrusion temperature of 220℃. S8: The molten material in the extruder enters the die head through the extruder distributor, and then the extrusion operation is carried out through the die head. The temperature of the die head is controlled at 230℃. The film thickness is adjusted by the die head gap to obtain the film material. S9: The membrane material obtained in S8 is rapidly cooled and shaped using a steel roller cooling method, with the cooling water temperature set to 20℃. S10: The shaped membrane material is fed into a stretching machine, wherein the longitudinal stretching ratio of the stretching machine is 2.1 times and the stretching temperature of the stretching machine is 80℃. S11: After being stretched, the membrane material is wound up at room temperature by a traction machine at a winding speed of 80m / min to obtain the finished biodegradable polyethylene breathable membrane. Example

[0018] This embodiment proposes a biodegradable polyethylene breathable membrane, comprising a PE substrate and a degradation masterbatch. The degradation masterbatch contains the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 6.5 parts maleic anhydride-grafted polypropylene, 0.4 parts stearic acid amine, 0.2 parts erucamide, and 0.5 parts stearic acid.

[0019] Reference Figure 1-2 This embodiment also proposes a method for preparing a biodegradable polyethylene breathable membrane, including the following steps: S1: The polycaprolactone is drawn into a drying chamber for drying. The drying temperature is set to 45℃ and the drying time is set to 3h, thereby removing trace amounts of moisture from the polycaprolactone for later use. S2: Polypropylene, maleic anhydride-grafted polypropylene, stearic acid amine, erucamide, stearic acid and polycaprolactone obtained in S1 are mixed in a closed mixer for 8 minutes and then fed into a twin-screw extruder. S3: The twin-screw extruder melts the material at a temperature of 155℃. The material extruded from the twin-screw extruder is then cut into particles by a pelletizer, dried by a dewatering machine, and degraded by a vibrating screen to remove defective products, thus obtaining degraded masterbatch. S4: Dry the PE substrate at 85°C for 2.5 hours to obtain a PE substrate with moisture removed; S5: The degradation masterbatch in S3 is dried at 55°C for 2.5 hours to obtain the dehydrated degradation masterbatch. S6: Add the PE substrate obtained in S4 and the degradation masterbatch obtained in S5 into the mixer at a ratio of 99:1 and mix for 5 minutes to obtain the mixed raw material; S7: The mixed raw material obtained in S6 is fed into the corresponding extruder. The extruder melts and plasticizes the raw material through the shearing action of the screw. The extruder is set to an extrusion temperature of 223℃. S8: The molten material in the extruder enters the die head through the extruder distributor, and then the extrusion operation is carried out through the die head. The temperature of the die head is controlled at 225℃. The film thickness is adjusted by the die head gap to obtain the film material. S9: The membrane material obtained in S8 is rapidly cooled and shaped using a steel roller cooling method, with the cooling water temperature set to 23℃. S10: The shaped membrane material is fed into a stretching machine, wherein the longitudinal stretching ratio of the stretching machine is 1.8 times and the stretching temperature of the stretching machine is 85℃. S11: After being stretched, the membrane material is wound up at room temperature by a traction machine at a winding speed of 80m / min to obtain the finished biodegradable polyethylene breathable membrane. Example

[0020] This embodiment proposes a biodegradable polyethylene breathable membrane, comprising a PE substrate and a degradation masterbatch. The degradation masterbatch contains the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 8 parts maleic anhydride-grafted polypropylene, 0.3 parts stearic acid amine, 0.1 parts erucamide, and 0.1 parts stearic acid.

[0021] Reference Figure 1-2 This embodiment also proposes a method for preparing a biodegradable polyethylene breathable membrane, including the following steps: S1: The polycaprolactone is drawn into a drying chamber for drying. The drying temperature is set to 50℃ and the drying time is set to -4h to remove trace amounts of moisture from the polycaprolactone for later use. S2: Polypropylene, maleic anhydride-grafted polypropylene, stearic acid amine, erucamide, stearic acid and polycaprolactone obtained in S1 are mixed in a closed mixer for 10 minutes and then fed into a twin-screw extruder. S3: The twin-screw extruder melts the material at a temperature of 150°C. The material extruded from the twin-screw extruder is then cut into particles by a pelletizer, dried by a dewatering machine, and degraded by a vibrating screen to remove defective products, thus obtaining degraded masterbatch. S4: Dry the PE substrate at 90°C for 2 hours to obtain a PE substrate with moisture removed; S5: The degradation masterbatch in S3 is dried at 60°C for 2 hours to obtain the dehydrated degradation masterbatch. S6: Add the PE substrate obtained in S4 and the degradation masterbatch obtained in S5 into the mixer at a ratio of 99:1 and mix for 5 minutes to obtain the mixed raw material; S7: The mixed raw material obtained in S6 is fed into the corresponding extruder. The extruder melts and plasticizes the raw material through the shearing action of the screw. The extruder is set to an extrusion temperature of 225℃. S8: The molten material in the extruder enters the die head through the extruder distributor, and then the extrusion operation is carried out through the die head. The temperature of the die head is controlled at 220℃. The film thickness is adjusted by the die head gap to obtain the film material. S9: The membrane material obtained in S8 is rapidly cooled and shaped using a steel roller cooling method, with the cooling water temperature set to 25℃. S10: The shaped membrane material is fed into a stretching machine, wherein the longitudinal stretching ratio of the stretching machine is 1.5 times and the stretching temperature of the stretching machine is 90℃. S11: After being stretched, the membrane material is wound up at room temperature by a traction machine at a winding speed of 80m / min to obtain the finished biodegradable polyethylene breathable membrane.

[0022] The biodegradable polyethylene breathable membranes prepared in Examples 1 to 3 of this paper were subjected to the following tests: (i) Biodegradation rate test: Refer to GB / T 19277.1-2011 "Determination of final aerobic biodegradation capacity of materials under controlled composting conditions by measuring carbon dioxide released", and conduct the test in a soil environment at 25±3℃ and 60±5% humidity. (II) Mechanical property testing: Tensile strength and elongation at break were determined in accordance with GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets"; (III) Processing performance evaluation: Record the melt pressure fluctuation value (≤±0.5MPa) and the number of defects on the membrane surface (≤3 / m²) during the membrane preparation process. The test results, obtained through biodegradability testing, mechanical property testing, and processing performance evaluation, are shown in the table below: The test results show that the biodegradable polyethylene breathable membrane prepared by the present invention is significantly better than traditional PE membranes and existing degradable PE membrane products in terms of degradation performance, achieving the expected technical goals. Among them, Example 3 is the best example.

Claims

1. A biodegradable polyethylene breathable membrane, characterized in that, It includes a PE substrate and a degradation masterbatch, wherein the degradation masterbatch contains the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 5-8 parts maleic anhydride-grafted polypropylene, 0.3-0.5 parts stearic acid amine, 0.1-0.3 parts erucamide and 0.1-1.0 parts stearic acid.

2. The biodegradable polyethylene breathable membrane according to claim 1, characterized in that, The degradation masterbatch comprises the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 5 parts maleic anhydride-grafted polypropylene, 0.5 parts stearic acid amine, 0.3 parts erucamide, and 1.0 part stearic acid.

3. The biodegradable polyethylene breathable membrane according to claim 1, characterized in that, The degradation masterbatch contains the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 6.5 parts maleic anhydride-grafted polypropylene, 0.4 parts stearic acid amine, 0.2 parts erucamide and 0.5 parts stearic acid.

4. The biodegradable polyethylene breathable membrane according to claim 1, characterized in that, The degradation masterbatch contains the following raw materials in parts by weight: 70 parts polypropylene, 20 parts polycaprolactone, 8 parts maleic anhydride-grafted polypropylene, 0.3 parts stearic acid amine, 0.1 parts erucamide and 0.1 parts stearic acid.

5. A method for preparing a biodegradable polyethylene breathable membrane, used to prepare the biodegradable polyethylene breathable membrane according to any one of claims 1-4, characterized in that, Includes the following steps: S1: The polycaprolactone is drawn into the drying drum for drying treatment, thereby removing trace amounts of moisture from the polycaprolactone and setting it aside for later use. S2: Polypropylene, maleic anhydride-grafted polypropylene, stearic acid amine, erucamide, stearic acid and polycaprolactone obtained in S1 are mixed in a closed mixer for 5-10 minutes and then fed into a twin-screw extruder. S3: The twin-screw extruder melts the material at a temperature of 150-160℃. The material extruded from the twin-screw extruder is then cut into particles by a pelletizer, dried by a dewatering machine, and degraded by a vibrating screen to remove defective products, thus obtaining degraded masterbatch. S4: Dry the PE substrate at 80-90℃ for 2-3 hours to obtain a PE substrate with moisture removed; S5: Dry the degradation masterbatch from S3 at 50-60℃ for 2-3 hours to obtain the dehydrated degradation masterbatch. S6: Add the PE substrate obtained in S4 and the degradation masterbatch obtained in S5 into the mixer at a ratio of 99:1 and mix for 5 minutes to obtain the mixed raw material; S7: The mixed raw material obtained in S6 is fed into the corresponding extruder, and the extruder achieves the melting and plasticization of the raw material through the shearing action of the screw. S8: The molten material in the extruder enters the die head through the distributor of the extruder, and is then extruded through the die head to obtain a film material; S9: The membrane material obtained in S8 is rapidly cooled and shaped using a steel roller cooling method; S10: The shaped membrane material is fed into a stretching machine, wherein the longitudinal stretching ratio of the stretching machine is 1.5-2.1 times, and the stretching temperature of the stretching machine is 80-90℃. S11: After being stretched, the membrane material is wound up at room temperature by a traction machine at a winding speed of 80m / min to obtain the finished biodegradable polyethylene breathable membrane.

6. The method for preparing a biodegradable polyethylene breathable membrane according to claim 5, characterized in that, In step S1, the drying temperature is set to 40-50℃ and the drying time is set to 2-4 hours.

7. The method for preparing a biodegradable polyethylene breathable membrane according to claim 6, characterized in that, In S7, the extrusion temperature of the extruder is set to 220-225℃.

8. The method for preparing a biodegradable polyethylene breathable membrane according to claim 7, characterized in that, In step S8, the temperature of the die head is controlled at 220-230℃, and the thickness of the film material is adjusted by the gap between the die heads.

9. The method for preparing a biodegradable polyethylene breathable membrane according to claim 8, characterized in that, In S9, the cooling water temperature for the steel roller cooling method is set to 20-25℃.

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