Outer-layer air-permeable film of isolation clothes and preparation method of outer-layer air-permeable film

Abstract

The invention provides an outer-layer breathable film of isolation clothes and a preparation method thereof, the outer-layer breathable film comprises the following raw materials by weight: 30-40 parts of polycaprolactone glycol, 5-7.5 parts of alpha-hydrogen-omega-hydroxyl-polydimethylsiloxane, 5-7.5 parts of 2, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4- The invention relates to a polyurethane elastomer, which is prepared from the following components in parts by weight: 1.5 to 2.5 parts of 2, 2-dimethylolpropionic acid, 4.5 to 6.3 parts of zinc-aluminum layered double hydroxide / nano-silver composite material, 2 to 3 parts of chain extender, 17 to 22 parts of diisocyanate, 1.2 to 1.8 parts of catalyst and 1000 parts of N, N-dimethylformamide. The film provided by the invention has excellent antibacterial performance, can endow the polyurethane film with more excellent microbial barrier performance, and also has excellent air permeability and moisture permeability, so that when the film is applied to preparation of isolation clothes, the isolation clothes have higher comfort.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer thin film materials, and particularly relates to an outer breathable film for isolation gowns and a preparation method thereof. Background Art

[0002] The primary task of the outer film of the isolation gown is to block external microorganisms such as bacteria, viruses, etc. to protect the safety of medical staff. The diameter of common bacteria is generally between 0.5 and 5 microns, and viruses are even as small as dozens of nanometers. The film needs to have a fine microporous structure or a dense molecular barrier to prevent them from penetrating. In addition, in a medical environment, medical staff may come into contact with various chemical disinfectants, volatile pharmaceutical substances, and harmful gases, and the film needs to have a certain chemical barrier ability.

[0003] Since polyurethane film has a good barrier effect on microorganisms such as bacteria and viruses, has a certain blocking effect on toxic and harmful chemical substances, and at the same time has excellent waterproof, breathable, and comfortable properties, it has a very good application effect as the outer film of the isolation gown. However, in order to enhance the barrier effect of the polyurethane film on bacteria, viruses, etc., it is generally achieved by increasing the density of the polyurethane film. However, the increase in the density of the polyurethane film will lead to a decrease in its breathable performance. An overly dense film layer will hinder air exchange, causing medical staff to feel stuffy and uncomfortable when wearing it, increasing the risk of sweating, and thus may affect the protection effect. Therefore, to ensure the comfort of the isolation gown, it is still necessary to maintain a high breathability. Under this requirement, the antibacterial and antiviral performance of the polyurethane film can be enhanced to strengthen its barrier effect on microorganisms such as bacteria and viruses.

[0004] To improve the antibacterial and antiviral performance of the polyurethane film, antibacterial and antiviral active substances can be added to it. The antibacterial and antiviral active substances can effectively inhibit or kill the microorganisms in contact with the film. Among them, silver nanoparticles are a kind of highly efficient antibacterial and antiviral active substances. However, when directly dispersed in the polyurethane film, they are prone to agglomeration and have poor stability, thus affecting their antibacterial and antiviral performance and the durability of the antibacterial and antiviral performance. And in view of the high demand for blocking microorganisms of the outer film of the isolation gown, it is also necessary to develop the compounding of silver nanoparticles with other antibacterial and antiviral active substances to further improve the antibacterial performance of the polyurethane film. Summary of the Invention

[0005] The purpose of the present invention is to provide an outer breathable film for isolation gowns and a preparation method thereof. The film has excellent antibacterial and antiviral properties, can endow the polyurethane film with more excellent microorganism barrier performance, and the film has excellent breathable and moisture-permeable properties, so that when the film is applied to the preparation of isolation gowns, the isolation gowns have high comfort.

[0006] To achieve the above purpose, the present invention is realized through the following technical solutions: The outer breathable film of an isolation suit comprises raw materials in the following parts by weight: 30-40 parts of polycaprolactone diol, 5-7.5 parts of α-hydrogen-ω-hydroxy-polydimethylsiloxane, 1.5-2.5 parts of 2,2-dimethylolpropionic acid, 4.5-6.3 parts of zinc-aluminum layered double hydroxide / nano silver composite material, 2-3 parts of chain extender, 17-22 parts of diisocyanate, 1.2-1.8 parts of catalyst, and 1000 parts of N,N-dimethylformamide.

[0007] Preferably, the molecular weight of the polycaprolactone diol is 2000-3000.

[0008] Preferably, the preparation method of the zinc-aluminum layered double hydroxide / nano silver composite material comprises the following steps: Put the quaternary ammonium salt intercalated modified zinc-aluminum layered double hydroxide into the nano silver sol, carry out ultrasonic treatment for 3-6 h, then filter, place the obtained material in a vacuum dryer at 70-80 °C for 32-48 h, and then grind and disperse to obtain the zinc-aluminum layered double hydroxide / nano silver composite material.

[0009] Preferably, the preparation method of the quaternary ammonium salt intercalated modified layered double hydroxide comprises the following steps: Add aluminum nitrate and zinc nitrate to water to prepare a metal nitrate solution; add sodium hydroxide and sodium carbonate to water to prepare an alkali solution; add a quaternary ammonium salt to water to prepare a quaternary ammonium salt aqueous solution; Under the condition of 50-55 °C, while stirring the quaternary ammonium salt aqueous solution, slowly add the metal nitrate solution, and at the same time add the alkali solution to keep the pH value of the reaction system between 9.5 and 10; after the addition of the metal nitrate solution is completed, continue to age at 65-70 °C for 20-30 h; then filter, wash, and vacuum dry to obtain the quaternary ammonium salt intercalated modified layered double hydroxide.

[0010] Preferably, the quaternary ammonium salt is at least one of tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, and octadecyltrimethylammonium chloride.

[0011] Preferably, in the metal nitrate solution, the concentration of aluminum nitrate is 0.4-0.5 mol / L, the concentration of zinc nitrate is 1.2-1.5 mol / L; the mass fraction of the quaternary ammonium salt aqueous solution is 1-1.5%; the volume ratio of the metal nitrate solution to the quaternary ammonium salt aqueous solution is 1:0.4-0.6; in the alkali solution, the solubility of sodium hydroxide is 0.9-1.5 mol / L, and the solubility of sodium carbonate is 0.3-0.5 mol / L.

[0012] Preferably, the preparation method of the nano silver sol comprises the following steps: Add 10 - 12 parts of water-soluble chitosan and 5 - 6 parts of glucose to 300 - 350 parts of water to prepare a chitosan / glucose mixed solution; add 1 - 1.2 parts of silver nitrate to 100 - 120 parts of water to prepare a silver nitrate solution. Then, while stirring the chitosan / glucose mixed solution, add the silver nitrate solution. After the addition is complete, perform ultrasonic treatment for 2 - 2.5 h with an ultrasonic power of 200 - 300 W to obtain silver nanosol.

[0013] Preferably, the diisocyanate is one or more of isophorone diisocyanate, 4,4 - diphenylmethane diisocyanate, and hexamethylene diisocyanate; the chain extender is at least one of ethylene glycol, 1,4 - butanediol, and 1,3 - propanediol; the catalyst is dibutyltin dilaurate.

[0014] As a general inventive concept, the present invention provides a method for preparing an outer breathable film of an isolation suit, comprising the following steps: Weigh each raw material of the outer breathable film of the isolation suit according to the ratio and prepare a polyurethane film precursor solution. Coat the above polyurethane film precursor solution on the release paper, first place it in a blast dryer at 75 - 80 °C for 3.5 - 5 h, then in a blast dryer at 125 - 130 °C for 3.5 - 5 h, cool to 40 - 50 °C, then soak it in water at 50 - 55 °C for 28 - 42 h, peel the film from the release paper, and dry it at 75 - 80 °C to obtain the outer breathable film of the isolation suit.

[0015] Preferably, the method for preparing the polyurethane film precursor solution comprises the following steps: First, place polycaprolactone diol, α - hydrogen - ω - hydroxy - polydimethylsiloxane, and diisocyanate in a reaction tank, stir and heat up to 80 - 90 °C under a nitrogen atmosphere and stir constantly for 0.5 - 1 h, add the catalyst, stir and react for 1.5 - 2 h, then cool down to 55 - 60 °C, then add 2,2 - dimethylolpropionic acid, the chain extender, and one - tenth amount of N,N - dimethylformamide, stir and react for 1.5 - 2.5 h, add zinc - aluminum layered double hydroxide / nanosilver composite material, continue to stir and react for 1.5 - 2 h, then perform ultrasonic treatment for 2 - 3 h, then cool down to below 50 °C, add the remaining amount of N,N - dimethylformamide, stir and mix to obtain the polyurethane film precursor solution.

[0016] The beneficial effects of the present invention are: 1. In the outer breathable film of the present invention, a zinc-aluminum layered double hydroxide / nano silver composite material is used as an antibacterial and antiviral active substance. It uses quaternary ammonium salt intercalated modified zinc-aluminum layered double hydroxide as a carrier to load nano silver, which can highly disperse nano silver in the polyurethane film. Moreover, zinc-aluminum layered double hydroxide also exhibits better antibacterial properties compared to other layered double hydroxides and carriers such as mesoporous silica. Further, through quaternary ammonium salt intercalated modification, the antibacterial and antiviral properties of the composite material are further enhanced.

[0017] 2. By intercalating and modifying zinc-aluminum layered double hydroxide with quaternary ammonium salt in the present invention, the structural stability of zinc-aluminum layered double hydroxide can be enhanced. At the same time, the nano silver sol in the present invention is a composite sol of nano silver and chitosan. Quaternary ammonium salt and chitosan attract each other through electrostatic interaction, hydrogen bond interaction, etc., and have a strong binding force. Therefore, the intercalation modification of quaternary ammonium salt can strengthen the adhesion between the nano silver sol and zinc-aluminum layered double hydroxide, so that the obtained quaternary ammonium salt intercalated modified zinc-aluminum layered double hydroxide exhibits excellent structural stability, and the outer breathable film shows more persistent and stable antibacterial properties, etc.

[0018] 3. The outer breathable film of the present invention is a polyurethane breathable film. It uses polycaprolactone diol as a reaction monomer, and by cooperating with an appropriate amount of α-hydrogen-ω-hydroxy-poly(dimethylsiloxane) as an auxiliary monomer, combined with other raw materials and preparation methods of the present invention, the prepared film can have excellent air permeability and moisture permeability. Detailed implementation mode

[0019] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0020] In the following examples, polycaprolactone diol was purchased from Hubei Maidehao Biotechnology Co., Ltd., CAS No. 36890-68-3, and the molecular weight was 2000; α-hydrogen-ω-hydroxy-poly(dimethylsiloxane) was purchased from Wuhan Kemike Biopharmaceutical Technology Co., Ltd., CAS No. 31692-79-2.

[0021] Example 1: The outer breathable film of an isolation gown comprises raw materials in the following parts by weight: 34 parts of polycaprolactone diol, 5 parts of α-hydrogen-ω-hydroxy-poly(dimethylsiloxane), 2 parts of 2,2-bis(hydroxymethyl)propionic acid, 4.7 parts of zinc-aluminum layered double hydroxide / nanosilver composite material, 3 parts of 1,4-butanediol, 20 parts of 4,4'-diphenylmethane diisocyanate, 1.2 parts of dibutyltin dilaurate, and 1000 parts of N,N-dimethylformamide.

[0022] In this embodiment, the preparation method of the zinc-aluminum layered double hydroxide / nanosilver composite material comprises the following steps: S1. Prepare quaternary ammonium salt intercalated modified zinc-aluminum layered double hydroxide: Add aluminum nitrate and zinc nitrate into water to prepare a metal nitrate solution. The concentration of aluminum nitrate in the metal nitrate solution is 0.4 mol / L, and the concentration of zinc nitrate is 1.2 mol / L. Add sodium hydroxide and sodium carbonate into water to prepare an alkali solution. The solubility of sodium hydroxide in the alkali solution is 0.9 mol / L, and the solubility of sodium carbonate is 0.3 mol / L. Add cetyltrimethylammonium chloride into water to prepare a quaternary ammonium salt aqueous solution with a mass fraction of 1.2%. Under the condition of 55 °C, while stirring the quaternary ammonium salt aqueous solution, slowly add the metal nitrate solution, and at the same time add the alkali solution to keep the pH value of the reaction system between 9.5 and 10. The volume ratio of the metal nitrate solution to the quaternary ammonium salt aqueous solution is 1:0.4. After the addition of the metal nitrate solution is completed, continue to age at 70 °C for 20 h. Then, filter, wash, and vacuum dry to obtain the quaternary ammonium salt intercalated modified layered double hydroxide.

[0023] S2. Prepare nanosilver sol: Add 10 parts of water-soluble chitosan and 5 parts of glucose into 300 parts of water to prepare a chitosan / glucose mixed solution. Add 1 part of silver nitrate into 100 parts of water to prepare a silver nitrate solution. Then, while stirring the chitosan / glucose mixed solution, add the silver nitrate solution. After the addition is completed, perform ultrasonic treatment for 2.5 h with an ultrasonic power of 220 W to obtain the nanosilver sol.

[0024] S3. Place the quaternary ammonium salt intercalated modified zinc-aluminum layered double hydroxide in the nanosilver sol, perform ultrasonic treatment for 6 h with an ultrasonic power of 500 W, then filter, place the obtained material in a vacuum dryer at 70 °C for 48 h, and then grind and disperse to obtain the zinc-aluminum layered double hydroxide / nanosilver composite material.

[0025] The preparation method of the outer breathable film of the isolation gown in this embodiment comprises the following steps: S1. Weigh each raw material of the outer breathable film of the isolation suit according to the ratio. First, put polycaprolactone diol, α-hydro-ω-hydroxy-poly(dimethylsiloxane), and diisocyanate into a reaction tank. Stir and heat up to 85 °C under a nitrogen atmosphere and keep stirring at a constant temperature for 1 h. Add dibutyltin dilaurate and stir for 2 h. Then cool down to 55 °C, add 2,2-dimethylolpropionic acid, 1,4-butanediol, and one-tenth of the amount of N,N-dimethylformamide, and stir for 2 h. Add zinc-aluminum layered double hydroxide / nanosilver composite material and continue to stir for 2 h. Then perform ultrasonic treatment for 2 h with an ultrasonic power of 200 W. Then cool down to below 50 °C and add the remaining amount of N,N-dimethylformamide and stir and mix for 2 h to obtain a polyurethane film precursor solution.

[0026] S2. Coat the above polyurethane film precursor solution on the release paper. First, place it in a blast dryer at 80 °C for 3.5 h, then in a blast dryer at 125 °C for 4 h, cool to 40 - 50 °C, then soak it in water at 50 °C for 36 h, peel the film off the release paper, and dry it at 75 °C to obtain the outer breathable film of the isolation suit.

[0027] Example 2: An outer breathable film of an isolation suit, comprising the following raw materials in parts by weight: 30 parts of polycaprolactone diol, 6 parts of α-hydro-ω-hydroxy-poly(dimethylsiloxane), 1.5 parts of 2,2-dimethylolpropionic acid, 4.5 parts of zinc-aluminum layered double hydroxide / nanosilver composite material, 2.2 parts of 1,4-butanediol, 17 parts of 4,4'-diphenylmethane diisocyanate, 1.3 parts of dibutyltin dilaurate, and 1000 parts of N,N-dimethylformamide.

[0028] In this example, the preparation method of the zinc-aluminum layered double hydroxide / nanosilver composite material includes the following steps: S1. Prepare quaternary ammonium salt intercalated modified zinc-aluminum layered double hydroxide: Add aluminum nitrate and zinc nitrate to water to prepare a metal nitrate solution. The concentration of aluminum nitrate in the metal nitrate solution is 0.5 mol / L, and the concentration of zinc nitrate is 1.5 mol / L. Add sodium hydroxide and sodium carbonate to water to prepare an alkali solution. The solubility of sodium hydroxide in the alkali solution is 1.5 mol / L, and the solubility of sodium carbonate is 0.5 mol / L. Add cetyltrimethylammonium chloride to water to prepare a quaternary ammonium salt aqueous solution with a mass fraction of 1.5%. Under the condition of 55 °C, while stirring the quaternary ammonium salt aqueous solution, slowly add the metal nitrate solution, and at the same time add an alkali solution to keep the pH value of the reaction system between 9.5 and 10. The volume ratio of the metal nitrate solution to the quaternary ammonium salt aqueous solution is 1:0.5. After the addition of the metal nitrate solution is completed, continue to age at 65 °C for 25 h. Then, after filtration, washing, and vacuum drying, the quaternary ammonium salt intercalated modified layered double hydroxide is obtained.

[0029] S2. Preparation of nano-silver sol: Add 10 parts of water-soluble chitosan and 5 parts of glucose to 300 parts of water to prepare a chitosan / glucose mixed solution; add 1 part of silver nitrate to 100 parts of water to prepare a silver nitrate solution. Then, while stirring the chitosan / glucose mixed solution, add the silver nitrate solution. After the addition is completed, perform ultrasonic treatment for 2.5 h with an ultrasonic power of 220 W to obtain the nano-silver sol.

[0030] S3. Place the quaternary ammonium salt intercalated modified zinc-aluminum layered double hydroxide in the nano-silver sol, perform ultrasonic treatment for 3 h with an ultrasonic power of 500 W, then filter, place the obtained material in vacuum drying at 75 °C for 40 h, and then grind and disperse to obtain the zinc-aluminum layered double hydroxide / nano-silver composite material.

[0031] The preparation method of the outer breathable film of the protective clothing in this example includes the following steps: S1. Weigh each raw material of the outer breathable film of the protective clothing according to the ratio. First, place polycaprolactone diol, α-hydro-ω-hydroxy-poly(dimethylsiloxane), and diisocyanate in a reaction tank, stir and heat up to 90 °C under a nitrogen atmosphere and keep stirring for 0.5 h. Add dibutyltin dilaurate, stir and react for 2 h, then cool down to 60 °C, add 2,2-dimethylolpropionic acid, 1,4-butanediol, and one-tenth amount of N,N-dimethylformamide, stir and react for 2.5 h, add the zinc-aluminum layered double hydroxide / nano-silver composite material, continue to stir and react for 1.5 h, then perform ultrasonic treatment for 3 h with an ultrasonic power of 200 W, and then cool down to below 50 °C, add the remaining amount of N,N-dimethylformamide, and stir and mix for 2 h to obtain the polyurethane film precursor solution.

[0032] S2. Coat the above polyurethane film precursor solution on the release paper, first place it in a blast dryer at 75 °C for 5 h, then in a blast dryer at 130 °C for 3.5 h, cool down to 40 - 50 °C, then soak it in water at 52 °C for 40 h, peel the film from the release paper, and dry it at 80 °C to obtain the outer breathable film of the protective clothing.

[0033] Example 3: The outer breathable film of an isolation gown comprises raw materials in the following parts by weight: 40 parts of polycaprolactone diol, 6.5 parts of α-hydro-ω-hydroxy-poly(dimethylsiloxane), 2.5 parts of 2,2-dimethylolpropionic acid, 6.3 parts of zinc-aluminum layered double hydroxide / nano silver composite material, 3 parts of 1,4-butanediol, 20 parts of 4,4'-diphenylmethane diisocyanate, 1.8 parts of dibutyltin dilaurate, and 1000 parts of N,N-dimethylformamide.

[0034] In this example, the preparation method of the zinc-aluminum layered double hydroxide / nano silver composite material is the same as that in Example 1. The preparation method of the outer breathable film of the isolation gown in this example is the same as that in Example 1.

[0035] Example 4: The outer breathable film of an isolation gown comprises raw materials in the following parts by weight: 36 parts of polycaprolactone diol, 7.5 parts of α-hydro-ω-hydroxy-poly(dimethylsiloxane), 2.2 parts of 2,2-dimethylolpropionic acid, 5.5 parts of zinc-aluminum layered double hydroxide / nano silver composite material, 2 parts of 1,4-butanediol, 22 parts of 4,4'-diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, and 1000 parts of N,N-dimethylformamide.

[0036] In this example, the preparation method of the zinc-aluminum layered double hydroxide / nano silver composite material is the same as that in Example 1. The preparation method of the outer breathable film of the isolation gown in this example is the same as that in Example 2.

[0037] Example 5: The outer breathable film of an isolation gown comprises raw materials in the following parts by weight: 33 parts of polycaprolactone diol, 7 parts of α-hydro-ω-hydroxy-poly(dimethylsiloxane), 2 parts of 2,2-dimethylolpropionic acid, 5.2 parts of zinc-aluminum layered double hydroxide / nano silver composite material, 2.5 parts of 1,4-butanediol, 19 parts of 4,4'-diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, and 1000 parts of N,N-dimethylformamide.

[0038] In this example, the preparation method of the zinc-aluminum layered double hydroxide / nano silver composite material is the same as that in Example 2. The preparation method of the outer breathable film of the isolation gown in this example is the same as that in Example 1.

[0039] Comparative Example 1: It is basically the same as Example 1, except that the zinc-aluminum layered double hydroxide / nano silver composite material is replaced with a magnesium-aluminum layered double hydroxide / nano silver composite material.

[0040] In this comparative example, the preparation method of the magnesium-aluminum layered double hydroxide / nano silver composite material is basically the same as that of the zinc-aluminum layered double hydroxide / nano silver composite material, except that zinc nitrate is replaced with magnesium nitrate.

[0041] Comparative Example 2: It is basically the same as Example 1, except that the zinc-aluminum layered double hydroxide / nano silver composite material is replaced by mesoporous silica supported nano silver in parts.

[0042] The preparation method of the mesoporous silica supported nano silver in this comparative example includes the following steps: Put mesoporous silica (particle size 200 - 900 nm) into the nano silver sol (prepared by the method in Example 1), perform ultrasonic treatment for 6 h, the ultrasonic power is 500 W, then filter, place the obtained material in a vacuum dryer at 70 °C for 48 h, and then grind and disperse to obtain the mesoporous silica supported nano silver.

[0043] Comparative Example 3: It is basically the same as Example 1, except that when preparing the zinc-aluminum layered double hydroxide / nano silver composite material, the zinc-aluminum layered double hydroxide is not modified by quaternary ammonium salt intercalation.

[0044] The preparation method of the zinc-aluminum layered double hydroxide / nano silver composite material in this comparative example includes the following steps: Put the zinc-aluminum layered double hydroxide into the nano silver sol, perform ultrasonic treatment for 6 h, the ultrasonic power is 500 W, then filter, place the obtained material in a vacuum dryer at 70 °C for 48 h, and then grind and disperse to obtain the zinc-aluminum layered double hydroxide / nano silver composite material.

[0045] The difference between the preparation steps of the zinc-aluminum layered double hydroxide and the preparation of the quaternary ammonium salt intercalated modified layered double hydroxide in Example 1 is that the quaternary ammonium salt aqueous solution is not prepared, and the used quaternary ammonium salt aqueous solution is replaced by the same mass of water.

[0046] Comparative Example 4: It is basically the same as Example 1, except that α-hydro-ω-hydroxy-polydimethylsiloxane is not added to the raw materials of the outer breathable film of the isolation suit. The outer breathable film of the isolation suit includes the following raw materials in parts by weight: 39 parts of polycaprolactone diol, 2 parts of 2,2-dimethylolpropionic acid, 4.7 parts of zinc-aluminum layered double hydroxide / nano silver composite material, 3 parts of 1,4-butanediol, 20 parts of 4,4-diphenylmethane diisocyanate, 1.2 parts of dibutyltin dilaurate, and 1000 parts of N,N-dimethylformamide.

[0047] Performance test: For the outer breathable films of the isolation suits prepared in Examples 1 - 5 and Comparative Examples 1 - 4, the thickness of the outer breathable film is 25 ± 1 μm, and the antibacterial performance of the outer breathable film is detected according to the standard of QB / T2591 - 2003. The specific test results are shown in Table 1.

[0048] Table 1: As can be seen from the above table, the outer breathable film of the isolation gowns in Examples 1 to 5 of the present invention has excellent antibacterial properties. Combining with the bacteria and virus barrier properties of the polyurethane film itself, the outer breathable film can effectively block external microorganisms. Moreover, after the outer breathable film is washed 5 times, it still has high antibacterial properties. It can be seen that the zinc-aluminum layered double hydroxide / nanosilver composite has strong stability in the polyurethane film and can maintain a high antibacterial effect for a long time.

[0049] As can be seen from the comparison between Example 1 and Comparative Example 1, if the zinc-aluminum layered double hydroxide / nanosilver composite is replaced with a magnesium-aluminum layered double hydroxide / nanosilver composite, the antibacterial effect will be reduced. It can be seen that compared with the magnesium-aluminum layered double hydroxide, the zinc-aluminum layered double hydroxide shows stronger antibacterial properties when combined with nanosilver.

[0050] As can be seen from the comparison between Example 1 and Comparative Example 2, if the carrier of nanosilver is replaced with mesoporous silica, its antibacterial performance will be significantly reduced.

[0051] As can be seen from the comparison between Example 1 and Comparative Example 3, quaternary ammonium salt modification of the zinc-aluminum layered double hydroxide will further enhance the antibacterial performance of the outer breathable film.

[0052] As can be seen from the comparison between Example 1 and Comparative Example 4, adding an appropriate amount of α-hydro-ω-hydroxy-polydimethylsiloxane to the polyurethane film of the present invention effectively enhances the antibacterial stability of the outer breathable film.

[0053] 2. For the outer breathable films of the isolation gowns prepared in Examples 1 to 5 and Comparative Examples 1 to 4, the thickness of the outer breathable film is 25 ± 1 μm; the oxygen permeability of the outer breathable film is tested according to the GB / T 1038-2000 standard; the moisture permeability of the outer breathable film is tested according to the ASTM E96 standard. The specific test results are shown in Table 1.

[0054] Table 1: Oxygen Permeation / mol / m·S·Pa <![CDATA[Water vapor transmission rate / g / (m 2 ·24 h)]]> Example 1 72 11870 Example 2 74 11980 Example 3 75 12030 Example 4 77 12050 Example 5 78 12120 Comparative Example 1 73 11850 Comparative Example 2 65 10120 Comparative Example 3 71 11430 Comparative Example 4 69 10900 As can be seen from the above table, the outer breathable film of the isolation gown of the present invention has excellent breathability and moisture permeability.

[0055] As can be seen from the comparison between Example 1 and Comparative Example 2, using the quaternary ammonium salt intercalated modified layered double hydroxide of the present invention as the carrier of nanosilver makes the oxygen permeability and moisture permeability stronger than those of mesoporous silica, and the film has better breathability and moisture permeability.

[0056] It can be seen from the comparison between Example 1 and Comparative Example 4 that adding an appropriate amount of α-hydro-ω-hydroxy-polydimethylsiloxane when preparing the polyurethane film of the present invention can enhance the gas permeability and moisture permeability of the film. The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An outer breathable film of an isolation suit, characterized in that: The invention comprises the following raw materials in parts by weight: 30-40 parts of polycaprolactone diol, 5-7.5 parts of α-hydrogen-ω-hydroxy-polydimethylsiloxane, 1.5-2.5 parts of 2,2-dihydroxymethylpropionic acid, 4.5-6.3 parts of zinc-aluminum layered double hydroxide / nanosilver composite material, 2-3 parts of chain extender, 17-22 parts of diisocyanate, 1.2-1.8 parts of catalyst and 1000 parts of N,N-dimethylformamide.

2. The outer breathable film of the isolation suit according to claim 1, characterized in that: The molecular weight of the polycaprolactone diol is 2000-3000.

3. The outer breathable film of the isolation suit according to claim 1, characterized in that: The preparation method of the zinc-aluminum layered double hydroxide / nanosilver composite material comprises the following steps: The quaternary ammonium salt intercalation modified zinc aluminum layered double hydroxide is placed in the nano silver sol, ultrasonically treated for 3-6 hours, and then filtered. The obtained material is placed at 70-80° C. and vacuum dried for 32-48 hours, and then ground and dispersed to obtain the zinc aluminum layered double hydroxide / nano silver composite material.

4. The outer breathable film of the isolation suit according to claim 3, characterized in that: The preparation method of the quaternary ammonium salt intercalation modified layered double hydroxide comprises the following steps: Aluminum nitrate and zinc nitrate are added to water to prepare a metal nitrate solution; sodium hydroxide and sodium carbonate are added to water to prepare an alkaline solution; quaternary ammonium salt is added to water to prepare a quaternary ammonium salt aqueous solution; At 50-55° C., slowly add the metal nitrate solution while stirring the quaternary ammonium salt aqueous solution, and simultaneously add the alkaline solution to keep the pH value of the reaction system between 9.5 and 10; after the metal nitrate solution is added, continue to age at 65-70° C. for 20-30 hours; then filter, wash, and vacuum dry to obtain a quaternary ammonium salt intercalation modified layered double hydroxide.

5. The outer breathable film of the isolation suit according to claim 4, characterized in that: The quaternary ammonium salt is at least one of tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride and octadecyltrimethylammonium chloride.

6. The outer breathable film of the isolation suit according to claim 4, characterized in that: In the metal nitrate solution, the concentration of aluminum nitrate is 0.4-0.5 mol / L, and the concentration of zinc nitrate is 1.2-1.5 mol / L; the mass fraction of the quaternary ammonium salt aqueous solution is 1-1.5%; the volume ratio of the metal nitrate solution to the quaternary ammonium salt aqueous solution is 1:0.4-0.6; in the alkaline solution, the solubility of sodium hydroxide is 0.9-1.5 mol / L, and the solubility of sodium carbonate is 0.3-0.5 mol / L.

7. The outer breathable film of the isolation suit according to claim 1, characterized in that: The preparation method of the nano silver sol comprises the following steps: Add 10-12 parts of water-soluble chitosan and 5-6 parts of glucose to 300-350 parts of water to prepare a chitosan / glucose mixed solution; add 1-1.2 parts of silver nitrate to 100-120 parts of water to prepare a silver nitrate solution; Then, the silver nitrate solution is added to the chitosan / glucose mixed solution while stirring. After the addition is completed, ultrasonic treatment is performed for 2 to 2.5 hours at an ultrasonic power of 200 to 300 W to obtain a nanosilver sol.

8. The outer breathable film of the isolation suit according to claim 1, characterized in that: The diisocyanate is one or more of isophorone diisocyanate, 4,4-diphenylmethane diisocyanate, and hexamethylene diisocyanate; the chain extender is at least one of ethylene glycol, 1,4-butanediol, and 1,3-propylene glycol; and the catalyst is dibutyltin dilaurate.

9. A method for preparing the outer breathable film of the isolation suit according to any one of claims 1 to 8, characterized in that: The following steps are involved: Weigh the raw materials of the outer breathable film of the isolation suit according to the proportions, and prepare a polyurethane film precursor solution; The polyurethane film precursor solution is coated on release paper, first dried at 75-80°C for 3.5-5h, then dried at 125-130°C for 3.5-5h, cooled to 40-50°C, and then immersed in water at 50-55°C for 28-42h, the film is peeled off from the release paper, and dried at 75-80°C to obtain the outer breathable film of the isolation suit.

10. The method for preparing the outer breathable film of the isolation suit according to claim 9, characterized in that: The method for preparing the polyurethane film precursor solution comprises the following steps: First, polycaprolactone diol, α-hydrogen-ω-hydroxy-polydimethylsiloxane and diisocyanate are placed in a reaction tank, stirred and heated to 80-90°C under a nitrogen atmosphere and stirred at a constant temperature for 0.5-1h, a catalyst is added, stirred and reacted for 1.5-2h, then the temperature is lowered to 55-60°C, 2,2-dihydroxymethylpropionic acid, a chain extender and one-tenth amount of N,N-dimethylformamide are added, stirred and reacted for 1.5-2.5h, zinc-aluminum layered double hydroxide / nanosilver composite material is added, stirred and reacted for 1.5-2h, ultrasonically treated for 2-3h, then the temperature is lowered to below 50°C, the remaining amount of N,N-dimethylformamide is added, and after stirring and mixing, a polyurethane film precursor solution is obtained.

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