Medical anti-fogging window PVC protective film and preparation method thereof

Abstract

The invention discloses a medical anti-fogging window PVC protective film and a preparation method thereof, and relates to the technical field of organic polymer materials. According to the invention, titanium dioxide, silicic acid sol and polyvinyl chloride are subjected to microwave cross-linking and blending, the binding force among components in a matrix is enhanced through the silicic acid sol, and the degradation harm of titanium dioxide to polyvinyl chloride is reduced; the titanium dioxide modified by neodymium, cerium and nitrogen enables the polyvinyl chloride to present a hydrophilic surface in a visible region through the photocatalysis of the titanium dioxide, so that a similar two-dimensional capillary effect is formed, spreading of water drops is facilitated, and an excellent anti-fog effect is achieved; the cationic center of a polyvinyl chloride'metastable huge complex 'is added in the matrix through rare earth elements neodymium and cerium, so that the compatibility among the components is enhanced, the stability of the matrix is enhanced, and the long-acting antifogging performance is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of organic polymer materials, and particularly to a medical anti-fogging window PVC protective film and a preparation method thereof. Background Art

[0002] PVC is a thermoplastic polymer produced by free radical polymerization and is a cost-effective alternative that can replace many rare natural resources. By adding different amounts of plasticizers, PVC can be transformed from a highly rigid material into a flexible one and can be processed into almost infinitely many products using a variety of equipment. PVC has been widely used due to its diverse processing methods and products, excellent durability and safety. At the same time, PVC is a material that can be recycled and reused, which is beneficial to energy conservation and environmental protection. PVC products are widely used in various industries such as construction, food packaging, and medical. Among them, plasticized PVC soft products are currently widely used in window protection film products due to their easy processing and high cost performance.

[0003] The fogging phenomenon widely exists in nature. The reason for its formation is that when warm and humid water vapor encounters a low-temperature interface (the temperature is lower than or equal to the dew point of water vapor corresponding to the pressure), the water vapor is suddenly cooled to reach the saturation state, and condensation and liquefaction will occur on the solid surface, eventually forming discrete fog droplets or an irregular water layer. When visible light passes through fog droplets and an irregular liquid surface, refraction and diffuse reflection phenomena will occur, resulting in a significant decrease in the light transmittance of the transparent substrate, affecting the lighting efficiency of the substrate, and bringing many inconveniences to people's life and production. For example, under fogging conditions, some optical devices cannot work properly, especially on the surface of functional transparent substrates, such as glasses, goggles, medical laparoscopes or other optical analysis instrument lenses; the fog droplets condensed on the windshield of airplanes and cars block the line of sight and even cause major traffic accidents; severe fogging phenomena also significantly reduce the utilization rate of light energy by agricultural greenhouse films and solar panels; the formation and accumulation of condensed water droplets will also lead to a decrease in the heat conduction efficiency of the low-temperature cold wall; in addition, the formation of fog droplets will also have a greater impact on food packaging and metal corrosion, causing certain economic losses. Under some extremely low-temperature conditions, water vapor undergoes the processes of ice nucleus formation, growth, diffusion, and adhesion, and a frost layer is formed on the substrate surface, which will seriously reduce the transmittance of the transparent substrate. Eliminating the temperature difference between the air environment and the transparent substrate is one of the effective anti-fogging strategies. By embedding electric heating elements inside the substrate or blowing hot air on the substrate surface to increase the air flow velocity and surface temperature of the substrate surface, when the substrate temperature > water vapor temperature ≥ dew point temperature, effective anti-fogging can be achieved. Due to its complex circuit element structure, high energy consumption and manufacturing cost, it does not conform to the production concept of green energy conservation and environmental protection, and its application is limited. Summary of the Invention

[0004] The purpose of the present invention is to provide a medical anti-fogging window PVC protective film and its preparation method to solve the problems existing in the prior art.

[0005] To solve the above technical problems, the present invention provides the following technical solutions: A medical anti-fogging window PVC protective film, including the following preparation steps:

[0006] (1) Mix cerium salt, neodymium salt, and deionized water to obtain a solution, and vaporize it into a gas;

[0007] (2) Dry the titanium gel under ammonia gas. After drying, evacuate the ammonia gas, and then introduce the gas, nitrogen, and argon described in step (1). The percentage of nitrogen in the total volume is 30%, and perform a calcination treatment. After the calcination is completed, grind to obtain modified titanium dioxide with a particle size of 80 nm;

[0008] (3) Mix the modified titanium dioxide and tetrahydrofuran in a mass ratio of 1:50, and perform ultrasonic treatment at 21 kHz for 15 - 30 min to obtain a titanium dioxide dispersion;

[0009] (4) Mix polyvinyl chloride and tetrahydrofuran, stir at 200 rpm for 1.5 - 3 h, add the titanium dioxide dispersion and silica sol, continue to stir for 5 - 8 h, let stand for 40 min, pour into a mold, perform microwave treatment, and then seal and dry for 48 h to obtain a medical anti-fogging window PVC protective film.

[0010] Further, the mass ratio of the cerium salt, neodymium salt, and deionized water in step (1) is 0.2:0.1:200.

[0011] Further, the cerium salt in step (1) is at least one of cerium chloride, cerium nitrate, cerium sulfate, and cerium acetate; the neodymium salt is at least one of neodymium chloride, neodymium nitrate, neodymium sulfate, and neodymium acetate.

[0012] Further, the flow rate of the gas in step (1) is 0.04 - 0.1 L / min.

[0013] Further, the temperature of the drying in step (2) is 110 - 130 °C and the time is 3 - 5 h.

[0014] Further, the temperature of the calcination in step (2) is 400 - 600 °C and the time is 3 - 5 h.

[0015] Further, the preparation method of the silica sol in step (4): Mix 35 wt% sulfuric acid aqueous solution, sodium silicate, and deionized water in a mass ratio of 1 - 4:0.5 - 1:50, and adjust the pH of the solution to 3 - 5 with ammonia water to obtain it.

[0016] Further, the molecular weight of the polyvinyl chloride in step (4) is 70000.

[0017] Further, the power of the microwave in step (4) is 200 - 300 W, and the time is 5 - 15 min.

[0018] Further, the mass ratio of polyvinyl chloride, tetrahydrofuran, titanium dioxide dispersion, and silica sol in step (4) is 10:100:1:2 - 10.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention uses titanium dioxide, silica sol, and polyvinyl chloride for blending. Under the action of the high-frequency electromagnetic field generated by the microwave, the silica sol grows explosively and uniformly into a crystal state and quickly condenses, thereby enhancing the binding force between the components in the matrix, and part of it forms silicon dioxide through condensation, thereby preventing the photocatalytic degradation of polyvinyl chloride by titanium dioxide and playing a protective role for the film. Moreover, the titanium dioxide modified by neodymium, cerium, and nitrogen makes the surface of polyvinyl chloride hydrophilic in the visible light region through its photocatalytic effect, causing the fog droplets to spread and form a water layer, reducing the adhesion of water droplets. At the same time, the oxygen vacancies and trivalent titanium formed by titanium dioxide under light irradiation form highly hydrophilic microregions around, while polyvinyl chloride makes the film present hydrophobic regions, thereby forming a two-dimensional capillary effect similar to that, which is conducive to the spreading of water droplets, thus achieving an excellent anti-fog effect. At the same time, by adding neodymium and cerium rare earth elements in the matrix to increase the cation centers of the "metastable giant complex" of polyvinyl chloride, the number of physical entanglement points increases, the compatibility between the components is enhanced, and the inorganic substances are well wrapped, thereby enhancing the stability of the matrix and achieving long-term anti-fog performance. Specific Embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a 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.

[0021] In order to more clearly illustrate the method provided by the present invention, the following examples are used for detailed description. The test methods for each index of the medical anti-fog window PVC protective film produced in the following examples are as follows:

[0022] Anti-fog: Take the same size of the example and the comparative example to conduct anti-fog performance testing according to GB / T2410, and detect their haze; place the samples in steam at 100 °C, let them stand for 30 min, take them out, dry them, and then detect their haze again.

[0023] Example 1; (1) Mix cerium chloride, neodymium sulfate, and deionized water to obtain a solution, and vaporize it into a gas; the mass ratio of cerium chloride, neodymium sulfate, and deionized water is 0.2:0.1:200;

[0024] (2) Dry the titanium gel under ammonia gas with a flow rate of 0.04 L / min at a temperature of 110 °C for 3 h. After drying, evacuate the ammonia gas, and then introduce the gas, nitrogen, and argon described in step (1). The percentage of nitrogen in the total volume is 30%, and perform a calcination treatment at a temperature of 400 °C for 3 h. After calcination, grind to obtain modified titanium dioxide with a particle size of 80 nm; the titanium gel is composed of tetrabutyl titanate, absolute ethanol, glacial acetic acid, and 5 wt% nitric acid-ethanol solution, and the mass ratio of its components is 10:30:2:15;

[0025] (3) Mix the modified titanium dioxide and tetrahydrofuran at a mass ratio of 1:50, and ultrasonicate at 21 kHz for 15 min to obtain a titanium dioxide dispersion;

[0026] (4) Mix 35 wt% sulfuric acid aqueous solution, sodium silicate, and deionized water at a mass ratio of 1:0.5:50, and adjust the pH of the solution to 3 with ammonia water to obtain a silica sol; mix polyvinyl chloride with a molecular weight of 70,000 and tetrahydrofuran, stir at 200 rpm for 1.5 h, add the titanium dioxide dispersion and the silica sol, continue to stir for 5 h, let stand for 40 min, pour into a mold, and perform microwave treatment at a power of 200 W for 5 min, and then seal and dry for 48 h to obtain a medical anti-fog window PVC protective film; the mass ratio of polyvinyl chloride with a molecular weight of 70,000, tetrahydrofuran, the titanium dioxide dispersion, and the silica sol is 10:100:1:2.

[0027] Example 2; (1) Mix cerium chloride, neodymium sulfate, and deionized water to obtain a solution, and vaporize it into a gas; the mass ratio of cerium chloride, neodymium sulfate, and deionized water is 0.2:0.1:200;

[0028] (2) Dry the titanium gel under ammonia gas with a flow rate of 0.07 L / min at a temperature of 120 °C for 4 h. After drying, evacuate the ammonia gas, and then introduce the gas, nitrogen, and argon described in step (1). The percentage of nitrogen in the total volume is 30%, and perform a calcination treatment at a temperature of 500 °C for 4 h. After calcination, grind to obtain modified titanium dioxide with a particle size of 80 nm; the titanium gel is composed of tetrabutyl titanate, absolute ethanol, glacial acetic acid, and 5 wt% nitric acid-ethanol solution, and the mass ratio of its components is 10:30:2:15;

[0029] (3) Mix the modified titanium dioxide and tetrahydrofuran at a mass ratio of 1:50, and ultrasonicate at 21 kHz for 22 min to obtain a titanium dioxide dispersion;

[0030] (4) Mix an aqueous sulfuric acid solution of 35 wt%, sodium silicate, and deionized water in a mass ratio of 2.5:0.75:50, and adjust the pH of the solution to 4 with ammonia water to obtain a silica sol; mix polyvinyl chloride with a molecular weight of 70,000 and tetrahydrofuran, stir at 200 rpm for 2 h, add a titanium dioxide dispersion and the silica sol, continue to stir for 7 h, let stand for 40 min, pour into a mold, and perform microwave treatment with a power of 250 W and a time of 10 min, and then seal and dry for 48 h to obtain a medical anti-fog window PVC protective film; the mass ratio of the polyvinyl chloride with a molecular weight of 70,000, tetrahydrofuran, the titanium dioxide dispersion, and the silica sol is 10:100:1:6.

[0031] Example 3; (1) Mix cerium chloride, neodymium sulfate, and deionized water to obtain a solution, and vaporize it into a gas; the mass ratio of cerium chloride, neodymium sulfate, and deionized water is 0.2:0.1:200;

[0032] (2) Perform a drying treatment on the titanium gel under ammonia gas with a flow rate of 0.1 L / min at a temperature of 130 °C for 5 h. After drying is completed, evacuate the ammonia gas, and then introduce the gas, nitrogen, and argon described in step (1). The percentage of nitrogen in the total volume is 30%, and perform a calcination treatment at a temperature of 600 °C for 8 h. After calcination is completed, grind to obtain modified titanium dioxide with a particle size of 80 nm; the titanium gel is composed of tetrabutyl titanate, absolute ethanol, glacial acetic acid, and a 5 wt% nitric acid-ethanol solution, and the mass ratio of its components is 10:30:2:15;

[0033] (3) Mix the modified titanium dioxide and tetrahydrofuran in a mass ratio of 1:50, and perform ultrasonic treatment at 21 kHz for 30 min to obtain a titanium dioxide dispersion;

[0034] (4) Mix an aqueous sulfuric acid solution of 35 wt%, sodium silicate, and deionized water in a mass ratio of 4:1:50, and adjust the pH of the solution to 5 with ammonia water to obtain a silica sol; mix polyvinyl chloride with a molecular weight of 70,000 and tetrahydrofuran, stir at 200 rpm for 3 h, add the titanium dioxide dispersion and the silica sol, continue to stir for 8 h, let stand for 40 min, pour into a mold, and perform microwave treatment with a power of 300 W and a time of 15 min, and then seal and dry for 48 h to obtain a medical anti-fog window PVC protective film; the mass ratio of the polyvinyl chloride with a molecular weight of 70,000, tetrahydrofuran, the titanium dioxide dispersion, and the silica sol is 10:100:1:10.

[0035] Comparative Example 1; (1) Mix titanium dioxide and tetrahydrofuran in a mass ratio of 1:50, and perform ultrasonic treatment at 21 kHz for 22 min to obtain a titanium dioxide dispersion;

[0036] (2) Mix an aqueous solution of 35 wt% sulfuric acid, sodium silicate, and deionized water in a mass ratio of 2.5:0.75:50, and adjust the pH of the solution to 4 with ammonia water to obtain a silica sol; mix polyvinyl chloride with a molecular weight of 70,000 and tetrahydrofuran, stir at 200 rpm for 2 h, add a titanium dioxide dispersion and the silica sol, continue to stir for 7 h, let stand for 40 min, pour into a mold, and perform microwave treatment with a power of 250 W and a time of 10 min, then seal and dry for 48 h to obtain a medical anti-fogging window PVC protective film; the mass ratio of the polyvinyl chloride with a molecular weight of 70,000, tetrahydrofuran, the titanium dioxide dispersion, and the silica sol is 10:100:1:6.

[0037] Comparative Example 2; The difference between Comparative Example 2 and Example 2 is that steps (1), (2), and (3) are absent, and step (4) is changed to: Mix an aqueous solution of 35 wt% sulfuric acid, sodium silicate, and deionized water in a mass ratio of 2.5:0.75:50, and adjust the pH of the solution to 4 with ammonia water to obtain a silica sol; mix polyvinyl chloride with a molecular weight of 70,000 and tetrahydrofuran, stir at 200 rpm for 2 h, add the silica sol, continue to stir for 7 h, let stand for 40 min, pour into a mold, and perform microwave treatment with a power of 250 W and a time of 10 min, then seal and dry for 48 h to obtain a medical anti-fogging window PVC protective film; the mass ratio of the polyvinyl chloride with a molecular weight of 70,000, tetrahydrofuran, and the silica sol is 10:100:6; the remaining steps are the same as in Example 2.

[0038] Comparative Example 3; (1) Mix cerium chloride, neodymium sulfate, and deionized water to obtain a solution, and vaporize it into a gas; the mass ratio of cerium chloride, neodymium sulfate, and deionized water is 0.2:0.1:200;

[0039] (2) Perform a drying treatment on the titanium gel under ammonia gas with a flow rate of 0.07 L / min at a temperature of 120 °C for 4 h. After drying is completed, evacuate the ammonia gas, and then introduce the gas, nitrogen, and argon described in step (1). The percentage of nitrogen in the total volume is 30%, and perform a calcination treatment at a temperature of 500 °C for 4 h. After calcination is completed, grind to obtain modified titanium dioxide with a particle size of 80 nm; the titanium gel is composed of tetrabutyl titanate, absolute ethanol, glacial acetic acid, and a 5 wt% nitric acid-ethanol solution, and the mass ratio of its components is 10:30:2:15;

[0040] (3) Mix the modified titanium dioxide and tetrahydrofuran in a mass ratio of 1:50, and ultrasonically treat at 21 kHz for 22 min to obtain a titanium dioxide dispersion;

[0041] (4) Mix polyvinyl chloride with a molecular weight of 70,000 and tetrahydrofuran, stir at 200 rpm for 2 h, add a titanium dioxide dispersion, continue stirring for 7 h, let stand for 40 min, pour into a mold, and perform microwave treatment with a power of 250 W and a time of 10 min, and then seal and dry for 48 h to obtain a medical anti-fogging window PVC protective film; the mass ratio of the polyvinyl chloride with a molecular weight of 70,000, tetrahydrofuran, and the titanium dioxide dispersion is 10:100:1.

[0042] Comparative Example 4; (1) Mix cerium chloride, neodymium sulfate, and deionized water to obtain a solution, and vaporize it into a gas; the mass ratio of cerium chloride, neodymium sulfate, and deionized water is 0.2:0.1:200;

[0043] (2) Perform a drying treatment on the titanium gel under an ammonia gas condition with a flow rate of 0.07 L / min, at a temperature of 120 °C and a time of 4 h. After drying is completed, evacuate the ammonia gas, and then introduce the gas, nitrogen, and argon described in step (1). The percentage of nitrogen in the total volume is 30%, and perform a calcination treatment at a temperature of 500 °C and a time of 4 h. After calcination is completed, grind to obtain modified titanium dioxide with a particle size of 80 nm; the titanium gel is composed of tetrabutyl titanate, absolute ethanol, glacial acetic acid, and a 5 wt% nitric acid-ethanol solution, and the mass ratio of its components is 10:30:2:15;

[0044] (3) Mix the modified titanium dioxide and tetrahydrofuran in a mass ratio of 1:50, and perform ultrasonic treatment at 21 kHz for 22 min to obtain a titanium dioxide dispersion;

[0045] (4) Mix a 35 wt% sulfuric acid aqueous solution, sodium silicate, and deionized water in a mass ratio of 2.5:0.75:50, adjust the pH of the solution to 4 with ammonia water to obtain a silica sol; mix polyvinyl chloride with a molecular weight of 70,000 and tetrahydrofuran, stir at 200 rpm for 2 h, add the titanium dioxide dispersion and the silica sol, continue stirring for 7 h, let stand for 40 min, pour into a mold, and seal and dry for 48 h to obtain a medical anti-fogging window PVC protective film; the mass ratio of the polyvinyl chloride with a molecular weight of 70,000, tetrahydrofuran, the titanium dioxide dispersion, and the silica sol is 10:100:1:6.

[0046] Effect Example

[0047] The following Table 1 gives the performance analysis results of the medical anti-fogging window PVC protective films using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

[0048] Table 1

[0049] Haze (%) Haze (100°C, 30 min, %) Example 1 0.5 0.7 Example 2 0.3 0.4 Example 3 0.4 0.6 Comparative Example 1 2.4 2.9 Comparative Example 2 3.7 4.0 Comparative Example 3 0.9 2.1 Comparative Example 4 1.2 2.3

[0050] From the comparison of the experimental data of the examples and the comparative examples in Table 1, it can be found that in the present invention, titanium dioxide, silica sol and polyvinyl chloride are blended, and under the action of the high-frequency electromagnetic field generated by microwave, the silica sol grows explosively and uniformly into a crystal state and quickly condenses, thereby enhancing the binding force between the components in the matrix, and part of it forms silicon dioxide through condensation, thereby preventing the photocatalytic degradation of polyvinyl chloride by titanium dioxide, playing a protective role for the film. Moreover, the titanium dioxide modified by neodymium, cerium and nitrogen makes the surface of polyvinyl chloride hydrophilic in the visible light region through its photocatalytic effect, so that the droplets diffuse to form a water layer, reducing the adhesion of water droplets. And the oxygen vacancies and trivalent titanium formed by titanium dioxide under light irradiation make highly hydrophilic microregions formed around, while polyvinyl chloride makes the film present hydrophobic regions, thereby forming a capillary effect similar to two dimensions, which is beneficial to the spreading of water droplets, thus achieving an excellent anti-fog effect. At the same time, by adding neodymium and cerium rare earth elements in the matrix to increase the cation centers of the "metastable giant complex" of polyvinyl chloride, the number of physical entanglement points increases, the compatibility between the components is enhanced, and the inorganic substances are well wrapped, thereby enhancing the stability of the matrix and realizing the long-term anti-fog performance.

[0051] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claim.

Claims

1. A medical anti-fogging window PVC protective film, characterized in that: The method comprises the following preparation steps: (1) mixing cerium salt, neodymium salt and deionized water to obtain a solution, and vaporizing the solution into a gas; (2) drying the titanium gel under ammonia, exhausting the ammonia after drying, and then introducing the gas described in step (1), nitrogen and argon, wherein the nitrogen accounts for 30% of the total volume, and calcining the titanium gel. After calcination, grinding the titanium gel to obtain modified titanium dioxide with a particle size of 80 nm; (3) mixing modified titanium dioxide and tetrahydrofuran in a mass ratio of 1:50, and ultrasonicating at 21 kHz for 15 to 30 minutes to obtain a titanium dioxide dispersion; (4) Mix polyvinyl chloride and tetrahydrofuran, stir at 200 rpm for 1.5 to 3 hours, add titanium dioxide dispersion and silicate sol, continue stirring for 5 to 8 hours, let stand for 40 minutes, pour into a mold, treat with microwaves, and then seal and dry for 48 hours to obtain a medical anti-fogging window PVC protective film.

2. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The mass ratio of the cerium salt, neodymium salt and deionized water in step (1) is 0.2:0.1:

200.

3. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The cerium salt in step (1) is at least one of cerium chloride, cerium nitrate, cerium sulfate and cerium acetate; the neodymium salt is at least one of neodymium chloride, neodymium nitrate, neodymium sulfate and neodymium acetate.

4. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The flow rate of the gas in step (2) is 0.04-0.1 L / min.

5. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The drying temperature in step (2) is 110-130° C. and the drying time is 3-5 hours.

6. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The calcination temperature in step (2) is 400-600° C. and the calcination time is 3-5 hours.

7. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The preparation method of the silicate sol in step (4) is as follows: 35wt% sulfuric acid aqueous solution, sodium silicate and deionized water are mixed in a mass ratio of 1-4:0.5-1:50, and the pH value of the solution is adjusted to 3-5 with ammonia water.

8. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The molecular weight of the polyvinyl chloride in step (4) is 70,000.

9. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The microwave power in step (4) is 200-300W and the time is 5-15min.

10. The medical anti-fogging window PVC protective film according to claim 1, characterized in that: The mass ratio of the polyvinyl chloride, tetrahydrofuran, titanium dioxide dispersion and silicate sol in step (4) is 10:100:1:2-10.