Preparation method and application of anti-fog polyvinyl alcohol-based film

Abstract

The invention discloses a preparation method and application of an antifogging polyvinyl alcohol-based film, and belongs to the technical field of antifogging surface preparation. The method comprises the following steps: firstly, preparing a polyvinyl alcohol aqueous solution, a glutaraldehyde aqueous solution, a magnesium chloride aqueous solution and a hydrochloric acid aqueous solution, mixing according to a volume ratio of 50: 1: 3: 1, stirring, carrying out ultrasonic treatment, casting on a target surface, and draining to form a polyvinyl alcohol-based film on the target surface. The polyvinyl alcohol-based film can be used for the inner sides of automobile windshields, goggles and the like made of glass or resin materials, has anti-fog and anti-frost effects, and has good light transmission, waterproofness and cleanability.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-fog surface preparation and relates to a preparation method of a polyvinyl alcohol-based film for anti-fog and application thereof. Background Art

[0002] Over the years, many scholars have conducted in-depth research in the field of anti-fogging and achieved many results. However, for some special service conditions, one side is often in a low-temperature environment and the other side is in a closed high-humidity environment, such as car glass, ski goggles, etc. This makes it difficult for traditional anti-fogging measures to fully play their role, or even freeze and fail.

[0003] Compared with direct processing on the surface, the use of additional thin films can minimize the impact on the performance of the material matrix and retain the original complete and mature molding process as much as possible. The methods of adding thin films to the surface in the prior art include dip coating, multi-layer coating and sol-gel method; among them, the dip coating method has high requirements on the target surface and environment, which increases the production cost; the thin film is formed on the surface of the lens by multi-layer coating, the coating steps are complicated, and the coating process requires high temperature, which has restrictions on the material of the target surface. Materials that are not resistant to high temperatures cannot be anti-fogging by this method; the sol-gel process is time-consuming and has low production efficiency. Summary of the invention

[0004] In order to solve the problems of high cost, low efficiency and material limitation of the prior art, the present invention provides a method for preparing a polyvinyl alcohol-based film for anti-fogging and its application. The prepared polyvinyl alcohol-based film has stable properties and structure, and can resist low temperature, freezing, water washing and immersion while achieving the anti-fogging purpose.

[0005] The method for preparing the anti-fogging polyvinyl alcohol-based film comprises the following steps:

[0006] Step 1, preparing a raw material solution, including a polyvinyl alcohol aqueous solution, a glutaraldehyde aqueous solution, a magnesium chloride aqueous solution and a hydrochloric acid aqueous solution;

[0007] The specific method for configuring each raw material solution is as follows:

[0008] Polyvinyl alcohol was dissolved in deionized water at 95° C. at a concentration of 0.1 g / mL to form a polyvinyl alcohol aqueous solution.

[0009] Glutaraldehyde was dissolved in deionized water at 0-8° C. at a concentration of 0.1 g / mL to form a glutaraldehyde aqueous solution.

[0010] Magnesium chloride was dissolved in deionized water at room temperature at a concentration of 0.1 g / mL to form a magnesium chloride aqueous solution.

[0011] A hydrochloric acid solution with a mass percent concentration of 35% was dissolved in room temperature deionized water at a volume ratio of 2:3 to form a hydrochloric acid aqueous solution.

[0012] Step 2: Evenly mix the polyvinyl alcohol aqueous solution, the glutaraldehyde aqueous solution, the magnesium chloride aqueous solution and the hydrochloric acid aqueous solution in a volume ratio of 50:1:3:1, and remove bubbles by ultrasound to obtain a mixed solution.

[0013] Sonicate the mixed solution for 10 s to remove air bubbles.

[0014] Step three: coating the mixed solution on a clean target surface and leaving it to stand for 6 hours to form a polyvinyl alcohol-based film on the target surface.

[0015] The polyvinyl alcohol-based film is composed of a polyvinyl alcohol hydrogel matrix and a magnesium chloride ion liquid. The polyvinyl alcohol is cross-linked with glutaraldehyde at this concentration and ratio, which can take into account the spreadability and waterproofness of the polyvinyl alcohol-based film; the cross-linking speed of the polyvinyl alcohol is controlled to be stable at ten minutes by using hydrochloric acid at this concentration and ratio, and the film can be quickly cross-linked and fixed after the coating is completed; the hydrophilic polyvinyl alcohol hydrogel matrix can spread the surface water into a water film, maintaining high transmittance and clarity; the polyvinyl alcohol hydrogel matrix and the target surface form a large number of hydrogen bonds, so that the film and the target surface are firmly connected; the molecular network of the polyvinyl alcohol hydrogel matrix fixes the magnesium chloride ion liquid, and the magnesium chloride ion liquid can reduce the freezing point of water, so that the film surface does not frost at low temperatures.

[0016] Polyvinyl alcohol-based films are used on the inside of windshields, goggles, etc., and have anti-fog and anti-frost functions. They also have good light transmittance, waterproofness and cleanability. Specifically, they are:

[0017] (1) Anti-fog property: When a lens coated with a polyvinyl alcohol-based film at room temperature is placed on water vapor emitted from 95°C water, the surface will not fog.

[0018] (2) Anti-frost property: When a lens coated with a polyvinyl alcohol-based film at -30°C is placed in air with a humidity of 30%, no frost will form on the surface; when a lens coated with a polyvinyl alcohol-based film at -30°C is placed on water vapor emitted by water at 95°C, no frost will form on the surface.

[0019] (3) Light transmittance: The light transmittance is maintained above 92%.

[0020] (4) Waterproofness: The surface of the lens coated with polyvinyl alcohol-based film remained unchanged after being immersed in water for 12 hours; the surface of the lens coated with polyvinyl alcohol-based film remained unchanged after being rinsed in 100 kPa water flow for 30 minutes.

[0021] (5) Cleanability: The surface stains of the lens coated with polyvinyl alcohol-based film can be removed by washing it in rain water; the surface stains of the lens coated with polyvinyl alcohol-based film can be removed by washing it in running water.

[0022] The advantages of the present invention are:

[0023] 1. The polyvinyl alcohol-based film of the present invention is suitable for various surfaces such as glass and resin, firmly adheres to the surface and maintains high light transmittance and clarity.

[0024] 2. The polyvinyl alcohol-based film prepared by the present invention has anti-fog and anti-frost capabilities within a wide range of temperature and humidity.

[0025] 3. The polyvinyl alcohol-based film prepared by the present invention has excellent durability and can withstand daily touch, pressing, soaking, flushing, cleaning, etc.

[0026] 4. In the method for preparing the polyvinyl alcohol-based film of the present invention, the raw materials are simple and easy to obtain, the preparation conditions are simple, and the anti-fogging purpose can be achieved on the target surface without complicated means. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : is a physical picture of the polyvinyl alcohol-based film prepared in the embodiment of the present invention; wherein Figure 1 aThe target surface is goggles; Figure 1 bThe target surface is a glass slide.

[0028] Figure 2 This is a light transmission effect diagram of the polyvinyl alcohol-based film prepared in an embodiment of the present invention.

[0029] Figure 3 : is a diagram showing the low-temperature and low-humidity anti-fogging effect of the polyvinyl alcohol-based film in an embodiment of the present invention; Figure 3 a is the initial surface; Figure 3 b is the final surface.

[0030] Figure 4 : is a diagram showing the low-temperature and high-humidity anti-fogging effect of the polyvinyl alcohol-based film in an embodiment of the present invention; Figure 4 a is the initial surface; Figure 4 b is the final surface.

[0031] Figure 5 This is a diagram showing the anti-fogging effect of the polyvinyl alcohol-based film at room temperature and high humidity in an embodiment of the present invention; Figure 5 a is the initial surface; Figure 5 b is the final surface.

[0032] Figure 6 : is a diagram showing the rainwater washing effect of the polyvinyl alcohol-based film in an embodiment of the present invention; Figure 6 a is the initial surface; Figure 6 b is the surface at the beginning of flushing; Figure 6 c is the surface during the flushing process; Figure 6 d is the final surface.

[0033] Figure 7 This is a water flow flushing effect diagram of the polyvinyl alcohol-based film in an embodiment of the present invention; Figure 7 a is the initial surface; Figure 7 b is the surface at the beginning of flushing; Figure 7 c is the surface during the flushing process; Figure 7 b is the final surface.

[0034] Figure 8 This is a diagram showing the water immersion effect of the polyvinyl alcohol-based film in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0036] In order to maintain the light transmittance, anti-fog and anti-frost capabilities, and to simultaneously meet the requirements of waterproof and washability, the present invention has developed a transparent polyvinyl alcohol-based film for anti-fog. The technical solution of the present invention is further described below in conjunction with the embodiments and drawings, but the content of the present invention is not limited to the following embodiments.

[0037] Example

[0038] A method for preparing a polyvinyl alcohol-based film for anti-fogging, comprising the following steps:

[0039] Step 1: dissolve polyvinyl alcohol in deionized water at 95° C. at a concentration of 0.1 g / mL to form a polyvinyl alcohol aqueous solution.

[0040] Step 2: dissolving glutaraldehyde at a concentration of 0.1 g / mL in deionized water at 0-8° C. to form a glutaraldehyde aqueous solution.

[0041] Step 3: dissolving magnesium chloride in deionized water at room temperature at a concentration of 0.1 g / mL to form a magnesium chloride aqueous solution.

[0042] Step 4: Dissolve 35% hydrochloric acid solution in room temperature deionized water at a volume ratio of 2:3 to form a hydrochloric acid aqueous solution.

[0043] Step 5: Mix the polyvinyl alcohol aqueous solution, the glutaraldehyde aqueous solution, the magnesium chloride aqueous solution and the hydrochloric acid aqueous solution in a ratio of 50:1:3:1. Stir the mixed solution at a speed of 600 r / min for 10 seconds to fully mix. Then, ultrasonicate the mixed solution for 10 seconds to remove bubbles.

[0044] Step six, cast the mixed solution on one side of the goggles and the glass slide respectively, drain the goggles and the glass slide and let it stand for 6 hours.

[0045] After completion, the actual effect is as follows Figure 1 As shown. Figure 1 a is the coating effect of the goggles, Figure 1 b is the coating effect of the glass slide. There is no visual difference between the coated and uncoated parts of the lens and the glass slide. Figure 2 As shown, there is no visual difference between the coated part and the uncoated part. Therefore, the polyvinyl alcohol-based film does not affect the clarity of the surface requiring anti-fogging.

[0046] The goggles coated with a polyvinyl alcohol-based film on one side were placed in a freezer chamber in a dry environment and cooled to -30°C, and then the goggles were taken out and placed in the air. Figure 3 As shown, Figure 3 a is the goggles just taken out, Figure 3 b: A few seconds after being taken out, frost can be observed on the side not coated with the polyvinyl alcohol-based film, while there is no change on the side coated with the polyvinyl alcohol-based film.

[0047] The goggles coated with a polyvinyl alcohol-based film on one side were placed in a freezer chamber in a dry environment and cooled to -30°C. The goggles were then taken out and placed in the mist generated by 95°C hot water. Figure 4 As shown, Figure 4 a is the goggles just taken out, Figure 4 b is that after a few seconds, frost can be observed on the side not coated with the polyvinyl alcohol-based film, while there is no change on the side coated with the polyvinyl alcohol-based film.

[0048] pass Figure 3 and Figure 4 From two experiments, it can be seen that coating with polyvinyl alcohol-based film has an anti-frost effect on goggles.

[0049] Place the goggles coated with a polyvinyl alcohol-based film on one side in the mist generated by 95°C hot water. Figure 5 As shown, after a few seconds, fog condensation can be observed on the side not coated with the polyvinyl alcohol-based film, while there is no change on the side coated with the polyvinyl alcohol-based film. Therefore, the polyvinyl alcohol-based film has an anti-fogging effect on the goggles.

[0050] like Figure 6 As shown, calcium carbonate powder is evenly sprinkled on the goggles surface coated with a polyvinyl alcohol-based film, and then droplets are continuously dripped onto the goggles surface. It can be observed that the calcium carbonate powder is washed away by the droplets, no calcium carbonate residue is left on the goggles surface, and the surface of the polyvinyl alcohol-based film does not change.

[0051] like Figure 7As shown, calcium carbonate powder is evenly sprinkled on the goggles surface coated with a polyvinyl alcohol-based film, and then the goggles surface is continuously rinsed with water. It can be observed that the calcium carbonate powder is rinsed clean by the water, no calcium carbonate residue is left on the goggles surface, and the surface of the polyvinyl alcohol-based film does not change.

[0052] pass Figure 6 and Figure 7 The experiments shown show that the polyvinyl alcohol-based film can be effectively cleaned by water droplets or water streams without causing wear of the polyvinyl alcohol-based film. The film is easy to clean and has wear resistance.

[0053] like Figure 8 As shown, the eye protection coated with the polyvinyl alcohol-based film was immersed in water for 24 hours, and the surface of the polyvinyl alcohol-based film did not change. Therefore, the polyvinyl alcohol-based film has good waterproof properties and can be used for a long time in an underwater environment.

Claims

1. A method for preparing a polyvinyl alcohol-based film for anti-fogging, characterized in that: The steps include: Step 1, preparing a raw material solution, including a polyvinyl alcohol aqueous solution, a glutaraldehyde aqueous solution, a magnesium chloride aqueous solution and a hydrochloric acid aqueous solution; Polyvinyl alcohol was dissolved in deionized water at 95° C. to form a polyvinyl alcohol aqueous solution with a concentration of 0.1 g / mL. Glutaraldehyde was dissolved in deionized water at 0-8°C to form a glutaraldehyde aqueous solution with a concentration of 0.1 g / mL. Magnesium chloride was dissolved in deionized water at room temperature to form a magnesium chloride aqueous solution with a concentration of 0.1 g / mL. A 35% hydrochloric acid solution was dissolved in room temperature deionized water at a volume ratio of 2:3 to form a hydrochloric acid aqueous solution. Step 2, uniformly mixing the polyvinyl alcohol aqueous solution, the glutaraldehyde aqueous solution, the magnesium chloride aqueous solution and the hydrochloric acid aqueous solution in a volume ratio of 50:1:3:1, and removing bubbles by ultrasound to obtain a mixed solution; Step three: coating the mixed solution on a clean target surface and leaving it to stand for 6 hours to form a polyvinyl alcohol-based film on the target surface.

2. The method for preparing a polyvinyl alcohol-based film for anti-fogging according to claim 1, characterized in that: Glutaraldehyde cross-links polyvinyl alcohol, taking into account the spreadability and waterproofness of the polyvinyl alcohol-based film; hydrochloric acid controls the cross-linking speed of polyvinyl alcohol to be stable at ten minutes, and quickly cross-links and fixes after coating.

3. The method for preparing a polyvinyl alcohol-based film for anti-fogging according to claim 1, characterized in that: The coating process is casting and draining.

4. A polyvinyl alcohol-based film for anti-fogging, characterized in that: The polyvinyl alcohol-based film is composed of a polyvinyl alcohol hydrogel matrix and a magnesium chloride ion liquid; the hydrophilic polyvinyl alcohol hydrogel matrix spreads the surface water into a water film, maintaining the high transmittance and clarity of the target surface; the polyvinyl alcohol hydrogel matrix and the target surface form a large number of hydrogen bonds, so that the polyvinyl alcohol-based film is firmly connected to the target surface; the molecular network of the polyvinyl alcohol hydrogel matrix fixes the magnesium chloride ion liquid, and the magnesium chloride ion liquid can lower the freezing point of water, so that the film surface does not frost at low temperatures.

5. The polyvinyl alcohol-based film according to claim 4, characterized in that Applied to glass or resin windshields or inside of goggles.

6. The polyvinyl alcohol-based film according to claim 4, characterized in that It has anti-fog and anti-frost functions, and has good light transmittance, waterproofness and cleanability. The specific performance is as follows: (1) Anti-fog property: When a lens coated with a polyvinyl alcohol-based film at room temperature is placed on water vapor emitted from 95°C water, the surface will not fog; (2) Frost resistance: When a lens coated with a polyvinyl alcohol-based film at -30°C is placed in air with a humidity of 30%, no frost will form on the surface; when a lens coated with a polyvinyl alcohol-based film at -30°C is placed on water vapor emitted by water at 95°C, no frost will form on the surface; (3) Light transmittance: The light transmittance of the lens coated with polyvinyl alcohol-based film remains above 92%; (4) Waterproofness: The surface of the lens coated with polyvinyl alcohol-based film remained unchanged after being immersed in water for 12 hours; the surface of the lens coated with polyvinyl alcohol-based film remained unchanged after being rinsed in 100 kPa water for 30 minutes; (5) Cleanability: When there are soluble stains on the lens coated with the polyvinyl alcohol-based film, placing it in rainwater or water flow to rinse can quickly remove the surface stains and keep the lens clean.

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