Waterproof breathable film with thermal insulation performance and preparation method thereof

Abstract

The invention relates to the technical field of waterproof gas-permeable membranes, in particular to a waterproof gas-permeable membrane with heat preservation performance and a preparation method thereof.The waterproof gas-permeable membrane with the heat preservation performance comprises a bio-based polymer, an ultraviolet light absorber, heat preservation filler, a plasticizer and a cross-linking agent.The bio-based polymer is selected from one or more of polylactic acid (PLA), polyhydroxyalkanoate (PHA) and cellulose ester; the ultraviolet light absorber is a mixture of nano-zinc oxide and nano-titanium dioxide, the thermal insulation filler is a combination of aerogel microspheres and hollow glass beads, the plasticizer is tributyl citrate or acetyl tributyl citrate, the cross-linking agent is a carbodiimide compound, and the filler is a mixture of nano-zinc oxide and nano-titanium dioxide. The materials are subjected to drying, blending, melt extrusion, stretching forming and heat treatment to finally obtain a waterproof breathable film with a heat preservation effect, and meanwhile, the waterproof breathable film also has an ultraviolet-proof function.

Description

Technical Field

[0001] The present invention relates to the technical field of waterproof breathable membranes, in particular to a waterproof breathable membrane with heat-insulating performance and a preparation method thereof. Background Art

[0002] Existing waterproof and breathable membranes are typically made from polytetrafluoroethylene resin supplemented with other fillers. The microporous structure of the polytetrafluoroethylene (PTFE) waterproof and breathable membrane achieves waterproofing, while the release of gas molecules on both sides of the membrane creates a breathable effect. However, such membranes are difficult to degrade and can cause damage to the natural environment. In line with the concept of sustainable development, the present invention provides a waterproof and breathable membrane with thermal insulation properties and a method for preparing the same. This thermal insulation membrane is primarily used in the medical field. Using a bio-based polymer as a base material, it incorporates UV absorbers and thermal insulation fillers to achieve both thermal insulation and sun protection properties. This membrane also addresses the issue of subsequent material degradation, significantly impacting ecological protection. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, the present invention provides a waterproof breathable membrane with thermal insulation performance and a preparation method thereof.

[0004] To solve the above technical problems, the present invention provides the following technical solutions: a waterproof breathable membrane with thermal insulation performance and a preparation method thereof, which comprises the following steps in parts by weight: Step 1. Weigh the material components: 40-60 parts of bio-based polymer, 10-20 parts of ultraviolet absorber, 20-30 parts of thermal insulation filler, 5-10 parts of plasticizer, and 2-5 parts of cross-linking agent; Step 2. Drying the materials: Place the bio-based polymer in a vacuum drying oven at 50-60°C for 24-48 hours to remove moisture; dry the UV absorber and thermal insulation filler at 80-100°C for 12-24 hours respectively; Step 3. Blending the materials: Turn on the high-speed mixer, adjust the speed to 800-1200 rpm, add the dried bio-based polymer, UV absorber, thermal insulation filler, plasticizer and cross-linking agent into the high-speed mixer and mix for 10-20 minutes; Step 4. Melt extrusion of the material; set the screw temperature to 150-180°C and the screw speed to 30-50 rpm, add the blended material from step 3 into a twin-screw extruder, and melt extrude to obtain a nascent film material; Step 5. Stretching the nascent film material; setting the stretching temperature of the hot stretching machine to 60-80°C and the stretching ratio to 2-4 times, and biaxially stretching the nascent film material; Step 6. Eliminate stress within the film; heat treat the stretched film material at 80-100° C. for 10-30 minutes.

[0005] As a preferred technical solution of the present invention, the bio-based polymer is one or more of polylactic acid (PLA), polyhydroxyalkanoate (PHA), and cellulose ester; The polylactic acid (PLA) is extracted from corn husks by first extracting starch from the corn husks, and then undergoing fermentation, concentration, vacuum purification, ring opening, polymerization and modification to obtain the PLA. The polyhydroxyalkanoate (PHA) is obtained by inoculating PHA fermentation bacteria, culturing the culture medium, fermenting, solid-liquid separation, ultrasonic cell wall breaking, plate-and-frame filtration, and extraction; The cellulose ester is extracted from cotton, and is prepared by mixing cotton, dimethyl sulfoxide and an organic base, then introducing carbon dioxide to react to obtain a cellulose-based CO2 reversible ionic liquid compound, then adding vinyl ester to react, and filtering, purifying and drying the mixture.

[0006] As a preferred technical solution of the present invention, the ultraviolet absorber is a mixture of nano zinc oxide and nano titanium dioxide, and the weight ratio of the two is 1:1-3:1.

[0007] As a preferred technical solution of the present invention, the thermal insulation filler is a combination of aerogel microspheres and hollow glass microspheres, and the weight ratio of the aerogel microspheres is 2:1-5:1.

[0008] As a preferred technical solution of the present invention, the plasticizer is tributyl citrate or acetyl tributyl citrate.

[0009] As a preferred technical solution of the present invention, the cross-linking agent is a carbodiimide compound.

[0010] Compared with the prior art, the present invention has the following beneficial effects: This waterproof and breathable membrane with thermal insulation performance and its preparation method use one or more of polylactic acid (PLA), polyhydroxyalkanoate (PHA), and cellulose ester as main raw materials, and are prepared by drying, blending, melt extrusion, stretching and eliminating internal stress. The membrane is waterproof and breathable. These biopolymers also have good biocompatibility and degradability, meet environmental protection requirements, and reduce pollution to the environment.

[0011] This waterproof and breathable membrane with thermal insulation properties and its preparation method, by combining nano zinc oxide and nano titanium dioxide as ultraviolet absorbers, combines nano zinc oxide and nano titanium dioxide in ultraviolet protection of different bands to form a better synergistic sun protection effect, helping patients' wounds resist the harm of ultraviolet rays and prevent pigmentation problems caused by ultraviolet rays on the wounds.

[0012] This waterproof breathable membrane with thermal insulation performance and its preparation method enhance the thermal insulation effect of the waterproof breathable membrane by combining thermal insulation fillers of aerogel microspheres and hollow glass microspheres, helping to maintain a constant temperature in the area where the waterproof breathable membrane is attached.

[0013] This waterproof and breathable membrane with thermal insulation properties and its preparation method, the use of plasticizer improves the processing performance and flexibility of the membrane material, allowing the membrane to better fit the patient's skin, and the cross-linking agent enhances the strength and stability of the membrane, making the membrane less likely to rupture, and can meet various needs in actual use.

[0014] The waterproof and breathable membrane with heat-insulating properties and its preparation method can prevent the injured part of the patient from coming into contact with water and becoming infected due to its waterproof property, while also having breathability to ensure that the skin can breathe normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, purpose and efficacy of the present invention easy to understand, the present invention is further described below in conjunction with specific examples, but the following examples are only preferred embodiments of the present invention, not all. Based on the examples in the embodiments, other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention. The experimental methods in the following examples, unless otherwise specified, are conventional methods, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0017] Working principle: A waterproof and breathable membrane with thermal insulation performance and its preparation method, calculated by weight, comprising the following steps: Step 1. Weigh the material components: 40-60 parts of bio-based polymer, 10-20 parts of ultraviolet absorber, 20-30 parts of thermal insulation filler, 5-10 parts of plasticizer, and 2-5 parts of cross-linking agent; Step 2. Drying the materials: Place the bio-based polymer in a vacuum drying oven at 50-60°C for 24-48 hours to remove moisture; dry the UV absorber and thermal insulation filler at 80-100°C for 12-24 hours respectively; Step 3. Blending the materials: Turn on the high-speed mixer, adjust the speed to 800-1200 rpm, add the dried bio-based polymer, UV absorber, thermal insulation filler, plasticizer and cross-linking agent into the high-speed mixer and mix for 10-20 minutes; Step 4. Material melt extrusion; set screw temperature to 150-180℃, screw speed to 30-50rpm, put the blended material of step 3. into the twin-screw extruder for melt extrusion to obtain the nascent film material; Step 5. Stretch the nascent film material; set the hot stretching machine stretching temperature to 60-80℃, stretching ratio to 2-4 times, and stretch the film material bidirectionally; Step 6. Eliminate the internal stress of the film; heat treat the stretched film material at 80-100℃ for 10-30 minutes.

[0018] The bio-based polymer is one or more of polylactic acid (PLA), polyhydroxyalkanoate (PHA), and cellulose ester; The extraction raw material of the polylactic acid (PLA) is corn husk, starch in the corn husk is extracted first, and then obtained through fermentation, concentration, vacuum purification, ring opening, polymerization and modification; The polyhydroxyalkanoate (PHA) is obtained through PHA fermentation strain inoculation, culture medium culture, fermentation, solid-liquid separation, ultrasonic cell disruption, plate and frame filtration and extraction; The extraction raw material of the cellulose ester is cotton, the cellulose-based CO2 reversible ionic liquid compound is obtained by mixing cotton, dimethyl sulfoxide and organic base and then charging carbon dioxide for reaction, then adding vinyl ester for reaction, and then filtering, purifying and drying the mixed solution.

[0019] The ultraviolet absorber is a mixture of nano zinc oxide and nano titanium dioxide, and the weight ratio of the two is 3:1.

[0020] The heat preservation filler is a combination of aerogel microspheres and hollow glass microbeads, and the weight ratio of the two is 2:1.

[0021] The plasticizer is tributyl citrate or acetyl tributyl citrate.

[0022] The crosslinking agent is a carbodiimide compound.

[0023] Weigh each material according to weight, put it into a vacuum drying oven for drying, then put it into a high-speed mixer for high-speed mixing, put the mixed material into a twin-screw extruder for melt extrusion, then put the melt-extruded nascent film material into a hot stretching machine for stretching, and finally heat treat to eliminate internal stress, thus obtaining a waterproof and breathable film with heat preservation performance which can be used for bandaging and protecting the wound of a patient.

[0024] Example 1: Step 1. Prepare the polylactic acid (PLA) required for the present invention. The PLA required in this example is prepared by first extracting starch from corn husks. The extracted starch is then converted into unrefined glucose, which is then fermented to produce lactic acid. The lactic acid monomer is then concentrated and converted into lactide. The resulting PLA is then vacuum purified, ring-opened, polymerized, and modified to obtain the PLA suitable for the present invention. Weigh the components; by weight, weigh 50 parts of polylactic acid (PLA), 15 parts of a mixture of nano-zinc oxide and nano-titanium dioxide (2:1 weight ratio), 25 parts of a combination of aerogel microspheres and hollow glass microspheres (3:1 weight ratio), 8 parts of tributyl citrate, and 3 parts of a carbodiimide crosslinker. Step 2. Drying the materials: PLA was dried in a vacuum drying oven at 55°C for 36 hours, and the UV absorber and thermal insulation filler were dried at 90°C for 18 hours respectively; Step 3. Blending the materials: Turn on the high-speed mixer and adjust the speed to 1000 rpm. Add the dried polylactic acid (PLA), a mixture of nano-zinc oxide and nano-titanium dioxide (weight ratio of 2:1), a combination of aerogel microspheres and hollow glass microspheres (weight ratio of 3:1), tributyl citrate, and a carbodiimide crosslinker into the high-speed mixer and mix for 15 minutes. Step 4. Melt extrusion of the material; setting the screw temperature to 165°C and the screw speed to 40 rpm, the blended material from step 3 was added to a twin-screw extruder and melt-extruded to obtain a nascent film material; Step 5. Stretching the nascent film material: setting the stretching temperature of the hot stretching machine to 70°C and the stretching ratio to 3 times, and biaxially stretching the nascent film material; Step 6. Eliminate the stress in the film; heat-treat the stretched film material at 90° C. for 20 minutes.

[0025] Example 2: Step 1. Prepare the polyhydroxyalkanoate (PHA) required for the present invention. Inoculate the PHA fermentation strain into a mineral salt culture medium containing a carbon source, a nitrogen source, and a phosphorus source for fermentation. Maintain the pH value of the fermentation environment at or above 7. Stir and aerate continuously during the fermentation process. Perform solid-liquid separation on the fermentation broth. Ultrasonic cell wall-breaking treatment is performed on the resulting bacterial precipitate. The broken bacterial cell is filtered on a plate to obtain a crude PHA product. Dichloromethane is added to extract the crude PHA product. Finally, the extract is purified to obtain refined PHA. Weigh each material component; weigh 45 parts of polyhydroxyalkanoate (PHA), 18 parts of a mixture of nano-zinc oxide and nano-titanium dioxide (weight ratio 3:1), 22 parts of a combination of aerogel microspheres and hollow glass microspheres (weight ratio 4:1), 6 parts of acetyl tributyl citrate, and 4 parts of a carbodiimide crosslinking agent. Step 2. Drying the materials: Dry the PHA in a vacuum drying oven at 50°C for 45 hours, and dry the UV absorber and thermal insulation filler at 90°C for 25 hours respectively; Step 3. Blending the materials: Turn on the high-speed mixer and adjust the speed to 1200 rpm. Add the dried PHA, the mixture of nano-zinc oxide and nano-titanium dioxide (weight ratio of 3:1), the combination of aerogel microspheres and hollow glass microspheres (weight ratio of 4:1), acetyl tributyl citrate, and a carbodiimide crosslinker into the high-speed mixer and mix for 10 minutes. Step 4. Melt-extrude the material; set the screw temperature to 170°C and the screw speed to 32 rpm, add the blended material from step 3 into a twin-screw extruder, and melt-extrude to obtain a nascent film material; Step 5. Stretching the nascent film material: setting the stretching temperature of the hot stretching machine to 80°C and the stretching ratio to 2.5 times, and biaxially stretching the nascent film material; Step 6. Eliminate the stress in the film; heat-treat the stretched film material at 95° C. for 15 minutes.

[0026] Example 3: The cellulose ester of the present invention uses cotton as a raw material. Cotton, dimethyl sulfoxide, and an organic base are mixed, carbon dioxide is introduced into the mixture, and the mixture is reacted at 80°C for 8 hours to obtain a cellulose-based CO2 reversible ionic liquid compound. Vinyl ester is then added to react, and water is added to the reaction mixture, which is filtered to retain the solid mixture. Finally, the cellulose ester is purified and dried to obtain the cellulose ester. Step 1. Weigh the various material components; by weight, weigh 55 parts of cellulose ester, 12 parts of a mixture of nano-zinc oxide and nano-titanium dioxide (weight ratio of 1:1), 28 parts of a combination of aerogel microspheres and hollow glass microspheres (weight ratio of 5:1), 7 parts of tributyl citrate, and 2.5 parts of a carbodiimide crosslinking agent; Step 2. Drying the materials: drying the cellulose ester in a vacuum drying oven at 60°C for 25 hours, and drying the UV absorber and the thermal insulation filler at 80°C for 22 hours respectively; Step 3. Blending the materials: Turn on the high-speed mixer and adjust the speed to 800 rpm. Add the dried cellulose ester, the mixture of nano-zinc oxide and nano-titanium dioxide, the combination of aerogel microspheres and hollow glass microspheres, tributyl citrate, and the carbodiimide crosslinking agent into the high-speed mixer and mix for 20 minutes. Step 4. Melt extrusion of the material; setting the screw temperature to 150°C and the screw speed to 30 rpm, the blended material from step 3 was added to a twin-screw extruder and melt-extruded to obtain a nascent film material; Step 5. Stretching the nascent film material: setting the stretching temperature of the hot stretching machine to 65°C and the stretching ratio to 3.5 times, and biaxially stretching the nascent film material; Step 6. Eliminate the stress in the film; heat-treat the stretched film material at 85° C. for 15 minutes.

[0027] The following table is a schematic diagram of the comparison between the waterproof breathable membrane prepared by the present invention and the traditional breathable membrane

[0028] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A waterproof breathable membrane with thermal insulation performance and a preparation method thereof, characterized in that: By weight, the method comprises the following steps: Step 1. Weigh the material components: 40-60 parts of bio-based polymer, 10-20 parts of ultraviolet absorber, 20-30 parts of thermal insulation filler, 5-10 parts of plasticizer, and 2-5 parts of cross-linking agent; Step 2. Drying the materials: Place the bio-based polymer in a vacuum drying oven at 50-60°C for 24-48 hours to remove moisture; dry the UV absorber and thermal insulation filler at 80-100°C for 12-24 hours respectively; Step 3. Blending the materials: Turn on the high-speed mixer, adjust the speed to 800-1200 rpm, add the dried bio-based polymer, UV absorber, thermal insulation filler, plasticizer and cross-linking agent into the high-speed mixer and mix for 10-20 minutes; Step 4. Melt extrusion of the material; set the screw temperature to 150-180°C and the screw speed to 30-50 rpm, add the blended material from step 3 into a twin-screw extruder, and melt extrude to obtain a nascent film material; Step 5. Stretching the nascent film material; setting the stretching temperature of the hot stretching machine to 60-80°C and the stretching ratio to 2-4 times, and biaxially stretching the nascent film material; Step 6. Eliminate stress within the film; heat treat the stretched film material at 80-100° C. for 10-30 minutes.

2. A waterproof breathable membrane with thermal insulation performance and a preparation method thereof according to claim 1, characterized in that: The bio-based polymer is one or more of polylactic acid, polyhydroxyalkanoate, and cellulose ester.

3. A waterproof breathable membrane with thermal insulation performance and a preparation method thereof according to claim 1, characterized in that: The ultraviolet absorber is a mixture of nano zinc oxide and nano titanium dioxide, with a weight ratio of 3:

1.

4. The waterproof breathable membrane with thermal insulation performance and the preparation method thereof according to claim 1, characterized in that: The thermal insulation filler is a combination of aerogel microspheres and hollow glass microspheres, with a weight ratio of the two being 2:

1.

5. The waterproof breathable membrane with thermal insulation performance and the preparation method thereof according to claim 1, characterized in that: The plasticizer is tributyl citrate or acetyl tributyl citrate.

6. The waterproof breathable membrane with thermal insulation performance and the preparation method thereof according to claim 1, characterized in that: The cross-linking agent is a carbodiimide compound.

7. The waterproof breathable membrane with thermal insulation performance and the preparation method thereof according to claim 1, characterized in that: The polylactic acid is extracted from corn husks. Starch is first extracted from the corn husks and then obtained through fermentation, concentration, vacuum purification, ring opening, polymerization and modification.

8. The waterproof breathable membrane with thermal insulation performance and the preparation method thereof according to claim 1, characterized in that: The polyhydroxyalkanoate is obtained through the processes of PHA fermentation bacteria inoculation, culture medium cultivation, fermentation, solid-liquid separation, ultrasonic cell wall breaking, plate-and-frame filtration and extraction.

9. The waterproof breathable membrane with thermal insulation performance and the preparation method thereof according to claim 1, characterized in that: The cellulose ester is extracted from cotton, and is prepared by mixing cotton, dimethyl sulfoxide and an organic base, then introducing carbon dioxide to react to obtain a cellulose-based CO2 reversible ionic liquid compound, then adding vinyl ester to react, and filtering, purifying and drying the mixture.

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