Antistatic and waterproof degradable plastic packaging film and preparation method thereof

Abstract

The invention relates to the technical field of modified plastic films, and provides an antistatic and waterproof degradable plastic packaging film and a preparation method thereof. The packaging film is based on a polyvinyl alcohol film, firstly 4-aminobenzoyl chloride reacts with hydroxyl on the surface of the polyvinyl alcohol film, an aniline group is introduced, then anilmomethyl triethoxy silane is used for modification, firstly, an aniline derivative is subjected to oxidative polymerization in an ice-water bath, and a silane structure is hydrolyzed to form silanol; and heating to condense the silanol to form polysiloxane, thereby obtaining the polyaniline / polysiloxane modified film. The polyaniline structural layer endows the film with antistatic property, and the polysiloxane structural layer improves the water resistance of the film, so that the polyvinyl alcohol packaging film with good water resistance and antistatic property is prepared.

Description

Technical Field

[0001] The invention relates to the technical field of modified plastic films and provides an antistatic, water-resistant and degradable plastic packaging film and a preparation method thereof. Background Art

[0002] Polyvinyl alcohol (PVA) film is biodegradable and can be broken down into harmless substances by microorganisms after use, making it a promising biodegradable packaging material. Its performance advantages include high barrier properties, high transparency, moderate antistatic properties, and good mechanical properties. It is suitable for use as food packaging, pharmaceutical packaging, medical device wrapping, and temporary coverings for electronic components.

[0003] Because polyvinyl alcohol (PVA) contains a large number of hydroxyl groups in its molecular structure, water molecules can easily penetrate into the film. Consequently, the water resistance of PVA films is poor, which, to a certain extent, limits their application. A common method to improve their water resistance is surface modification, where a modifier reacts with the surface hydroxyl groups to convert them into hydrophobic groups or chains.

[0004] However, while the above modification method improves the water resistance of polyvinyl alcohol film, it will also lead to a decrease in its antistatic performance. The reasons are: It's well known that the antistatic properties of polyvinyl alcohol films stem from the presence of numerous hydroxyl groups in their molecular structure, which absorb surrounding water and form a thin, conductive water film on the film's surface, preventing static electricity buildup. However, the aforementioned modification method converts hydroxyl groups into hydrophobic groups or chains, making it difficult for the modified film's surface to form a water film.

[0005] It can be seen that it is difficult to obtain a polyvinyl alcohol packaging film with good water resistance and antistatic properties by using common surface modification methods. Summary of the Invention

[0006] In view of the above situation, the present invention proposes an antistatic, water-resistant and degradable plastic packaging film and a preparation method thereof, the purpose of which is to obtain a polyvinyl alcohol packaging film with good water resistance and antistatic properties.

[0007] To achieve the above purpose, the specific technical solutions involved in the present invention are as follows: The first aspect of the present invention provides a method for preparing an antistatic, water-resistant, degradable plastic packaging film, comprising the following steps: (1) Spray a dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of a polyvinyl alcohol film, and react with ultrasonic oscillation under N2 protection for a certain period of time. Remove the film, wash it, and dry it; (2) Spray a hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film, place it in an ice water bath, spray an ammonium persulfate hydrochloric acid solution under N2 protection, and react with ultrasonic oscillation for a certain period of time; (3) Place the film in an oil bath and heat it for a certain period of time, wash it, and dry it to obtain a polyaniline / polysiloxane modified film.

[0008] First, the surface of the polyvinyl alcohol film was modified with 4-aminobenzoyl chloride. The acyl chloride groups reacted with the hydroxyl groups on the film surface to connect the aniline structure to the film surface.

[0009] Preferably, in the solution of step (1), the concentration of 4-aminobenzoyl chloride is 1-2 mol / L, and the concentration of triethylamine is 1-2 mol / L.

[0010] Preferably, the spraying amount of the solution in step (1) on the film surface is 5-10 mL / m 2 .

[0011] Preferably, in step (1), the reaction process is: first react at 0-2°C for 0.5-2h, and then react at 10-20°C for 3-6h.

[0012] Then, the film surface was further modified with anilinemethyltriethoxysilane. This was done in two stages: The first stage, step (2), involves oxidative polymerization of the aniline derivative in an acidic medium. This stage must be carried out at low temperatures. The polymerization involves the aniline structure of anilinemethyltriethoxysilane and the aniline structure introduced onto the film surface in step (1). During the polymerization reaction, the silane structure gradually hydrolyzes to form silanols.

[0013] Preferably, in the hydrochloric acid solution of anilinemethyltriethoxysilane in step (2), the concentration of HCl is 1 mol / L, and the concentration of anilinemethyltriethoxysilane is 0.5-1 mol / L.

[0014] Furthermore, the spraying amount of the hydrochloric acid solution of anilinemethyltriethoxysilane on the film surface is 20-60mL / m 2 .

[0015] Preferably, in the hydrochloric acid solution of ammonium persulfate in step (2), the concentration of HCl is 1 mol / L, and the concentration of ammonium persulfate is 0.5-1 mol / L.

[0016] Furthermore, the spraying amount of the hydrochloric acid solution of ammonium persulfate on the film surface is 40-60% of the spraying amount of the hydrochloric acid solution of anilinemethyltriethoxysilane.

[0017] Preferably, in step (2), the reaction time is 12-18 hours.

[0018] The second stage is step (3): through heating reaction, the silanol structure on the surface of the film undergoes condensation reaction to form polysiloxane.

[0019] Preferably, in step (3), the reaction temperature is 105-115°C and the reaction time is 1-2 hours.

[0020] A second aspect of the present invention provides an antistatic, water-resistant, degradable plastic packaging film. The packaging film is based on a polyvinyl alcohol film and is obtained by surface modification using the above-mentioned method, namely, first reacting 4-aminobenzoyl chloride with hydroxyl groups on the surface of the polyvinyl alcohol film to introduce aniline groups on the film surface, and then modifying the film using anilinemethyltriethoxysilane. First, the aniline derivative is oxidatively polymerized in an ice-water bath, and the silane structure is hydrolyzed to form silanols. Then, heating is performed to condense the silanols to form polysiloxane, thereby obtaining a polyaniline / polysiloxane modified film.

[0021] The present invention provides an antistatic, water-resistant, degradable plastic packaging film and a preparation method. Compared to existing technologies, the present invention's outstanding features and superior performance lie in the following: Through the modification method of the present invention, a polyaniline structural layer and a polysiloxane structural layer are sequentially formed on the surface of a polyvinyl alcohol film. On the one hand, the polyaniline structural layer imparts a certain degree of conductivity to the film surface, promoting charge transfer and preventing charge accumulation, thereby providing an antistatic effect. On the other hand, the polysiloxane structural layer exhibits excellent hydrophobicity, preventing water molecules from penetrating the film and improving the film's water resistance. Thus, the present invention produces a polyvinyl alcohol packaging film with both excellent water resistance and antistatic properties. DETAILED DESCRIPTION

[0022] In order to prepare a polyvinyl alcohol packaging film having good water resistance and antistatic properties, the present invention adopts the following preparation method: (1) Spray a dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of a polyvinyl alcohol film, and react with ultrasonic oscillation under N2 protection for a certain period of time. Remove the film, wash it, and dry it; (2) Spray a hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film, place it in an ice water bath, spray an ammonium persulfate hydrochloric acid solution under N2 protection, and react with ultrasonic oscillation for a certain period of time; (3) Place the film in an oil bath and heat it for a certain period of time, wash it, and dry it to obtain a polyaniline / polysiloxane modified film.

[0023] In the solution of step (1), the concentration of 4-aminobenzoyl chloride is 1-2 mol / L, and the concentration of triethylamine is 1-2 mol / L.

[0024] The spraying amount of the solution in step (1) on the film surface is 5-10mL / m 2 .

[0025] In step (1), the reaction process is: first react at 0-2°C for 0.5-2h, and then react at 10-20°C for 3-6h.

[0026] In the hydrochloric acid solution of anilinemethyltriethoxysilane in step (2), the concentration of HCl is 1 mol / L, and the concentration of anilinemethyltriethoxysilane is 0.5-1 mol / L; the spraying amount of the hydrochloric acid solution of anilinemethyltriethoxysilane on the film surface is 20-60 mL / m 2 .

[0027] In the hydrochloric acid solution of ammonium persulfate in step (2), the concentration of HCl is 1 mol / L, and the concentration of ammonium persulfate is 0.5-1 mol / L; the amount of the hydrochloric acid solution of ammonium persulfate sprayed on the film surface is 40-60% of the amount of the hydrochloric acid solution of anilinemethyltriethoxysilane sprayed.

[0028] In step (2), the reaction time is 12-18 hours.

[0029] In step (3), the reaction temperature is 105-115°C and the reaction time is 1-2h.

[0030] We fixed the concentration of each solution used above, fixed the reaction temperature, changed the solution spraying amount and reaction time, and carried out the experiment of the embodiment. In the dichloromethane solution of 4-aminobenzoyl chloride and triethylamine, the concentrations of 4-aminobenzoyl chloride and triethylamine are both 1 mol / L.

[0031] In the hydrochloric acid solution of anilinemethyltriethoxysilane, the concentrations of HCl and anilinemethyltriethoxysilane are both 1 mol / L.

[0032] In the hydrochloric acid solution of ammonium persulfate, the concentrations of HCl and ammonium persulfate are both 1 mol / L. Example 1

[0033] (1) Spray the dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of the polyvinyl alcohol film at a spraying volume of 10 mL / m 2 , react with ultrasonic oscillation under N2 protection, first react at 0℃ for 1h, then react at 15℃ for 4h, take out the film, wash and dry; (2) Spray the hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film at a spraying rate of 20 mL / m 2 , placed in an ice water bath, sprayed with ammonium persulfate hydrochloric acid solution under N2 protection, the spraying amount is 10mL / m 2 , ultrasonic oscillation reaction for 12h; (3) Place the film in an oil bath, heat at 110°C for 60 min, wash, and dry to obtain a polyaniline / polysiloxane modified film. Example 2

[0034] (1) Spray the dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of the polyvinyl alcohol film at a spraying volume of 10 mL / m 2 , react with ultrasonic oscillation under N2 protection, first react at 0℃ for 1h, then react at 15℃ for 4h, take out the film, wash and dry; (2) Spray the hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film at a spraying volume of 30 mL / m 2 , placed in an ice water bath, sprayed with ammonium persulfate hydrochloric acid solution under N2 protection, the spraying amount is 15mL / m 2 , ultrasonic oscillation reaction for 13.5h; (3) Place the film in an oil bath, heat at 110°C for 75 minutes, wash, and dry to obtain a polyaniline / polysiloxane modified film. Example 3

[0035] (1) Spray the dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of the polyvinyl alcohol film at a spraying volume of 10 mL / m 2 , react with ultrasonic oscillation under N2 protection, first react at 0℃ for 1h, then react at 15℃ for 4h, take out the film, wash and dry; (2) Spray the hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film at a spraying rate of 40 mL / m 2 , placed in an ice water bath, sprayed with ammonium persulfate hydrochloric acid solution under N2 protection, the spraying amount is 20mL / m 2 , ultrasonic oscillation reaction for 15h; (3) Place the film in an oil bath, heat at 110°C for 90 min, wash, and dry to obtain a polyaniline / polysiloxane modified film. Example 4

[0036] (1) Spray the dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of the polyvinyl alcohol film at a spraying volume of 10 mL / m 2 , react with ultrasonic oscillation under N2 protection, first react at 0℃ for 1h, then react at 15℃ for 4h, take out the film, wash and dry; (2) Spray the hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film at a spraying volume of 50 mL / m 2 , placed in an ice water bath, sprayed with ammonium persulfate hydrochloric acid solution under N2 protection, the spraying amount is 25mL / m 2 , ultrasonic oscillation reaction for 16.5h; (3) Place the film in an oil bath, heat at 110°C for 105 min, wash, and dry to obtain a polyaniline / polysiloxane modified film. Example 5

[0037] (1) Spray the dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of the polyvinyl alcohol film at a spraying volume of 10 mL / m 2 , react with ultrasonic oscillation under N2 protection, first react at 0℃ for 1h, then react at 15℃ for 4h, take out the film, wash and dry; (2) Spray the hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film at a spraying volume of 60 mL / m 2 , placed in an ice water bath, sprayed with ammonium persulfate hydrochloric acid solution under N2 protection, the spraying amount is 30mL / m 2 , ultrasonic oscillation reaction for 18h; (3) Place the film in an oil bath, heat at 110°C for 120 min, wash, and dry to obtain a polyaniline / polysiloxane modified film.

[0038] Performance testing: (1) The unmodified polyvinyl alcohol film and the modified films prepared in Examples 1-5 were placed in an environment with a relative humidity of 65% and a temperature of 25°C for 48 hours. The surface resistivity was then tested according to GB / T 1410-2006. The same sample was tested five times and the average value was taken. The test results are shown in Table 1. (2) 5 μL of water was dropped onto the surface of the unmodified polyvinyl alcohol film and the modified film prepared in Examples 1-5, respectively. The water contact angle was measured using an optical contact angle meter at a test temperature of 25°C. The same sample was tested 5 times and the average value was taken. The test results are shown in Table 1. (3) Referring to GB / T 1040.3-2006, the modified films prepared in Examples 1-5 were made into standard samples. Half of the samples in each group were directly tested for dry tensile strength, and the other half were immersed in deionized water for 24 h and then tested for wet tensile strength. The test conditions were: temperature 25°C, relative humidity 50%, and tensile speed 50 mm / min. The same sample was tested 5 times and the average value was taken. The strength retention rate was calculated by dividing the wet tensile strength by the dry tensile strength. The calculation results are shown in Table 1.

[0039] Table 1:

Claims

1. A method for preparing an antistatic, water-resistant, degradable plastic packaging film, characterized in that: The method comprises the following preparation steps: (1) Spray a dichloromethane solution of 4-aminobenzoyl chloride and triethylamine onto the surface of a polyvinyl alcohol film, and react with ultrasonic oscillation under N2 protection for a certain period of time. Remove the film, wash it, and dry it; (2) Spray a hydrochloric acid solution of aniline methyl triethoxysilane onto the surface of the film, place it in an ice water bath, spray an ammonium persulfate hydrochloric acid solution under N2 protection, and react with ultrasonic oscillation for a certain period of time; (3) Place the film in an oil bath and heat it for a certain period of time, wash it, and dry it to obtain a polyaniline / polysiloxane modified film.

2. The preparation method according to claim 1, characterized in that In the solution of step (1), the concentration of 4-aminobenzoyl chloride is 1-2 mol / L, and the concentration of triethylamine is 1-2 mol / L.

3. The preparation method according to claim 1, characterized in that: The spraying amount of the solution in step (1) on the film surface is 5-10mL / m 2 .

4. The preparation method according to claim 1, characterized in that In step (1), the reaction process is: first react at 0-2°C for 0.5-2h, and then react at 10-20°C for 3-6h.

5. The preparation method according to claim 1, characterized in that: In the hydrochloric acid solution of anilinemethyltriethoxysilane in step (2), the concentration of HCl is 1 mol / L, and the concentration of anilinemethyltriethoxysilane is 0.5-1 mol / L; the spraying amount of the hydrochloric acid solution of anilinemethyltriethoxysilane on the film surface is 20-60 mL / m 2 .

6. The preparation method according to claim 1, characterized in that: In the hydrochloric acid solution of ammonium persulfate in step (2), the concentration of HCl is 1 mol / L, and the concentration of ammonium persulfate is 0.5-1 mol / L; the amount of the hydrochloric acid solution of ammonium persulfate sprayed on the film surface is 40-60% of the amount of the hydrochloric acid solution of anilinemethyltriethoxysilane sprayed.

7. The preparation method according to claim 1, characterized in that: In step (2), the reaction time is 12-18 hours.

8. The preparation method according to claim 1, characterized in that: In step (3), the reaction temperature is 105-115°C and the reaction time is 1-2h.

9. The antistatic, water-resistant, degradable plastic packaging film prepared by the preparation method according to any one of claims 1 to 8.

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