CN111621141B - A slow-release chlorine dioxide-water-based polyurethane antibacterial film and preparation method thereof - Google Patents

Abstract

The invention discloses a slow-release chlorine dioxide-water-based polyurethane antibacterial film and a preparation method thereof, belonging to the field of antibacterial materials. The preparation method of the invention includes two major steps. The first step is to synthesize an aqueous polyurethane dispersion. The raw materials are hard segment, soft segment, 2,2-dimethylolpropionic acid, triethylamine, acetone and catalyst dibutyltin dilaurate; the second step is the preparation of chlorine dioxide-water-based polyurethane antibacterial film, which is added to the dispersion liquid A stable chlorine dioxide aqueous solution is added, and a slow-release chlorine dioxide-water-based polyurethane antibacterial film is prepared by a casting method; the carboxylic acid in the film is used as an acid activator for reacting with chlorine dioxide, and chlorine dioxide gas can be produced to make the film The material has antibacterial properties, and at the same time, the release of chlorine dioxide gas is controlled by the release of carboxylic acid in the film, so as to achieve a certain slow-release effect.

Description

A slow-release chlorine dioxide-water-based polyurethane antibacterial film and preparation method thereof

technical field

The invention relates to the field of antibacterial materials, in particular to a slow-release chlorine dioxide-water-based polyurethane antibacterial film and a preparation method thereof.

Background technique

Antibacterial film is the most widely used form of antibacterial packaging, mainly because of its low preparation cost, wide application range, and obvious bacteriostatic effect, so antibacterial film has a good application prospect. The antibacterial effect of the antibacterial film is mainly determined by the added antibacterial agent, and different antibacterial agents have a great influence on the antibacterial effect of the antibacterial film. As far as antibacterial agents are concerned, antibacterial films can be divided into organic antibacterial films, inorganic antibacterial films and natural antibacterial films.

Water-based polyurethane (WPU) uses water as a solvent, which is environmentally friendly, pollution-free, and has no toxic side effects. It has gradually replaced polyurethane (PU) as a more green and environmentally friendly synthetic material. Waterborne polyurethane also has good compatibility, mechanical properties and film-forming properties, and can be used as a film substrate.

Chlorine dioxide (ClO ₂ ) has the advantages of efficient bactericidal effect, no pollution to the environment, and no three causes (carcinogenic, teratogenic, mutagenic) substances when used, so it is listed by the World Health Organization as one of the safe disinfection substances. A1 grade product, chlorine dioxide is also widely used in water treatment, air purification, medical treatment, food preservation and other fields. In daily production, gaseous chlorine dioxide is easily decomposed when exposed to light or heat, and liquid chlorine dioxide is unstable. In contrast, solid chlorine dioxide has strong stability, convenient storage and transportation, and has a certain slow-release effect. However, solid chlorine dioxide still has some defects, such as chlorine dioxide is prone to burst release in the slow-release stage, and its release rate is difficult to control, etc. These problems need to be solved urgently. At present, the patent documents that mention controlling the release rate of chlorine dioxide have the following technical solutions:

Cui Jian invented a method for preparing a formaldehyde-removing chlorine dioxide slow-release gel, which includes the steps of mixing sodium gluconate, a gelling agent, and a chlorine dioxide precursor to obtain a chlorine dioxide gel system; adding a polymer The steps of obtaining an activated chlorine dioxide slow-release gel system with ethylene glycol and an acidic reagent; the steps of adding barium sulfate to the above-mentioned system to obtain a stable activated chlorine dioxide gel system.

Shanghai Ocean University invented a method for preparing a chlorine dioxide sustained-release fresh-keeping gel, the chlorine dioxide sustained-release fresh-keeping gel includes a gel layer A and a gel layer B, and the preparation raw materials of the gel layer A include a shell polysaccharide, sodium hydroxide aqueous solution and sodium chlorite, the preparation raw materials of the gel layer B include chitosan, acetic acid aqueous solution, acidic substance, and glutaraldehyde aqueous solution; in application, the gel layer A and all The gel layer B can be pasted together.

Qingdao Agricultural University invented a micro-controlled release high-efficiency gas preservation material, which includes sodium chlorite, citric acid, ferrous chloride, ferrous sulfate, ferrous ammonium sulfate, silica gel, gelatin, polyacrylamide, sodium alginate , β-cyclodextrin, deionized water, according to the preparation process thereof, a fresh-keeping material with 1-4 layers of chlorine dioxide sandwich layers can be prepared.

Ningbo University invented a long-acting slow-release chlorine dioxide preservative, which is composed of tablet and powder. The tablet is mainly composed of silica gel adsorbent, sodium chlorite, microporous network structure forming agent, ion field forming agent and water. ;Powder is mainly composed of weak acid activator, silica gel adsorbent, water and binder, and then put the tablet and powder into a breathable non-woven bag. When using, squeeze the packaging bag slightly and place it in a humid environment.

However, most of the above-mentioned researchers have directly added sodium chlorite powder and organic acid to the preparation of chlorine dioxide antibacterial materials. Sodium chlorite is a precursor to generate chlorine dioxide, which is directly mixed in the material, is unstable under light, high temperature, and high humidity conditions, and is easily decomposed, which limits the yield and effect of chlorine dioxide to a certain extent. time.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a slow-release chlorine dioxide-water-based polyurethane antibacterial film and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art, so that the antibacterial film can achieve the controlled release effect on chlorine dioxide, prolong its Slow release time to achieve long-term antibacterial and fresh-keeping effect.

For achieving the above object, the present invention provides the following scheme:

The invention provides a preparation method of a slow-release chlorine dioxide-water-based polyurethane antibacterial film. A stable chlorine dioxide aqueous solution is added to the water-based polyurethane dispersion, stirred and mixed evenly, put into a mold, and air-dried at room temperature to form a film. Slow-release chlorine dioxide-water-based polyurethane antibacterial film;

The preparation method of the water-based polyurethane dispersion comprises the following steps:

Under the protective atmosphere, add the soft segment and 2,2-hydroxymethylpropionic acid, add acetone under stirring, heat for the first time, and stir, add the catalyst dropwise, then add the hard segment and acetone, condense and reflux, add three Ethylamine and acetone, for the second heating;

After the heating is stopped, it is cooled, and distilled water is added dropwise to react to obtain an aqueous polyurethane dispersion.

Further, in each raw material, the total molar ratio of isocyanide to hydroxyl is 1.4:1, and the molar ratio of triethylamine to 2,2-dimethylolpropionic acid is 1:1.

Further, when adding acetone for the first time, the stirring rate of the stirring condition is 150-250r/min, the addition amount of the acetone is 10%-200% of the molar amount of the soft segment, and the amount of acetone added each time is the same. .

Further, the temperature of the first heating is 40-50° C., and the stirring time after heating is 20-30 min.

Further, before dropping the catalyst, the solution system is required to be colorless and transparent.

Further, the heating time of the second heating is 1 h.

Further, the dropping process of the distilled water is carried out under stirring, and the cooling is cooling to below 10°C;

Before adding distilled water dropwise, the stirring speed is 900-1100r/min, and the dropping speed is 2-3s/drop. When the solution system shows the phenomenon from thick to thin, adjust the stirring speed to 400-600r/min.

Further, the added amount of the stable chlorine dioxide aqueous solution is 6%-30% of the volume of the aqueous polyurethane dispersion.

Further, the catalyst is dibutyltin dilaurate, and the addition amount is 0.25ml.

Further, the hard segment is one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate; The segment is one or more of polytetrahydrofuran, polytrimethylene ether glycol, polycaprolactone glycol, and polycarbonate glycol with a molecular weight of 1000 to 3000.

The present invention also provides a slow-release chlorine dioxide-water-based polyurethane antibacterial film prepared by the above-mentioned preparation method of the slow-release chlorine dioxide-water-based polyurethane antibacterial film.

The present invention discloses the following technical effects:

1) The base material of the antibacterial film is water-based polyurethane, which has the advantages of non-toxicity, no pollution to the environment, easy processing, good compatibility, excellent mechanical properties and film-forming properties, and can be used as food packaging materials.

2) Under the preparation process conditions of the present invention, the prepared slow-release chlorine dioxide/aqueous polyurethane antibacterial film has a tensile strength of 10.0-11.8MPa, a breaking elongation of about 450%-530%, and a The water vapor transmission rate is 100-120g/(m ² ·24h), the oxygen transmission rate of the membrane is 3.3-6.2cm ³ ·m ^-2 ·24h ^-1 , and the antibacterial rate of the antibacterial film can reach more than 98%.

3) For the first time, the carboxylic acid in the water-based polyurethane film is used as the activator, and without adding other acidic reagents, ClO ₂ - and acid are used to react at a uniform speed under the excitation of water to produce chlorine dioxide gas, which improves the slow-release effect and effectively improves the The explosive release phenomenon of chlorine dioxide gas is prone to occur during the release process.

Instruction drawings

Fig. 1 is the plan view of the slow-release chlorine dioxide-water-based polyurethane antibacterial film prepared in Example 1;

2 is a cross-sectional view of the slow-release chlorine dioxide-water-based polyurethane antibacterial film prepared in Example 1.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail, which detailed description should not be construed as a limitation of the invention, but rather as a more detailed description of certain aspects, features, and embodiments of the invention.

It should be understood that the terms described in the present invention are only used to describe particular embodiments, and are not used to limit the present invention. Additionally, for numerical ranges in the present disclosure, it should be understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in that stated range is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention relates. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials in connection with which the documents are referred. In the event of conflict with any incorporated document, the content of this specification controls.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present invention without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the present invention. The description and examples of the present application are only exemplary.

Example 1

1) Synthesis of aqueous polyurethane dispersion:

Add 62.9109g of polytetrahydrofuran and 2.4842g of 2,2-dimethylolpropionic acid to a 500ml round-bottom four-necked flask equipped with a digital display stirrer, temperature control device, and Ar protective gas; adjust the stirring speed to 200r /min, add 125ml of acetone during stirring; after connecting the serpentine condenser tube, wrap the interface with Teflon raw material tape to ensure tightness.

The heating temperature was controlled between 40-50 °C by the temperature control device, and heated and stirred for 20 minutes. When the solution in the four-necked flask was colorless and transparent, 0.25 ml of catalyst (dibutyltin dilaurate) was added dropwise after 5 minutes. 15.54g of isophorone diisocyanate and equal amount of acetone were added to the catalyst after 5min; when the temperature in the four-necked flask reached about 70°C, the condenser tube began to condense and reflux, and after 4 hours of condensate reflux, 1.8724g of triethyl ether was then added. amine and the same amount of acetone; stop heating after adding triethylamine for one hour, and when the temperature in the four-necked flask drops below 10 °C, remove the condenser tube, connect a constant pressure funnel with 160 ml of distilled water, and use The speed of 6ml/min was added dropwise (the speed of the stirrer was adjusted to 1000r/min before dropping), and the solution in the flask would show a phenomenon of thickening and thinning during the dropping process. At this time, the speed of the stirrer was adjusted to 500r/min. min to prevent the solution from splashing to the inner wall of the flask; after the dropwise addition of the distilled water in the constant pressure funnel is completed, the aqueous polyurethane dispersion can be obtained by reacting for another 30 min, and the aqueous polyurethane dispersion is poured into a silk-mouth bottle and sealed for storage.

2) Preparation of chlorine dioxide-water-based polyurethane antibacterial film:

Measure 30ml of the aqueous polyurethane dispersion prepared in step 1) with a measuring cylinder, add 2ml of stable aqueous solution of chlorine dioxide, stir and mix the two evenly, and pour it into a square polytetrafluoroethylene mold placed horizontally. Naturally air-dried for 24 hours to form a film to obtain a slow-release chlorine dioxide-water-based polyurethane antibacterial film.

The tensile strength of the antibacterial film prepared in Example 1 can reach 10.5MPa, the elongation at break is 460%, the water vapor transmission rate of the film is 112g/(m ² ·24h), and the oxygen transmission rate of the film is 4.6cm ³ ·m ^-2 ·24h ^-1 , the antibacterial rate of the antibacterial film can reach more than 98%.

Example 2

1) Synthesis of aqueous polyurethane dispersion:

Add 48.2248g of polytetrahydrofuran and 3.4826g of 2,2-dimethylolpropionic acid to a 500ml round-bottom four-necked flask equipped with a digital display stirrer, temperature control device, and Ar protective gas; adjust the stirring speed to 200r /min, add 100ml of acetone during stirring; after connecting the serpentine condenser tube, wrap the interface with Teflon raw material tape to ensure tightness.

The heating temperature was controlled between 40-50 °C by the temperature control device, and heated and stirred for 20 minutes. When the solution in the four-necked flask was colorless and transparent, 0.25 ml of catalyst (dibutyltin dilaurate) was added dropwise after 5 minutes. 15.54g of isophorone diisocyanate and an equal amount of acetone were added to the catalyst after 5 minutes; when the temperature in the four-necked flask reached about 70°C, the condenser tube began to condense and reflux, and after 4 hours of condensate reflux, 2.6250g of triethyl ether was then added. amine and the same amount of acetone; stop heating one hour after adding triethylamine, and when the temperature in the four-necked flask drops below 10 °C, remove the condenser tube, connect a constant pressure funnel with 140 ml of distilled water, and use Dropwise at a speed of 6ml/min (adjust the speed of the stirrer to 900r/min before dropping), the solution in the flask will show a phenomenon of thickening and thinning during the dropping process, at this time, adjust the speed of the stirrer to 450r/min. min to prevent the solution from splashing to the inner wall of the flask; wait until the end of the dropwise addition of distilled water in the constant pressure funnel, and then react for 30 min to obtain an aqueous polyurethane dispersion, and pour the aqueous polyurethane dispersion into a silk neck bottle and seal it for storage.

2) Preparation of chlorine dioxide-water-based polyurethane antibacterial film:

Measure 50ml of the aqueous polyurethane dispersion prepared in step 1) with a measuring cylinder, add 5ml of stable chlorine dioxide aqueous solution, stir and mix the two evenly, and pour it into a horizontal square polytetrafluoroethylene mold. Naturally air-dried for 24 hours to form a film to obtain a slow-release chlorine dioxide-water-based polyurethane antibacterial film.

The tensile strength of the antibacterial film prepared in Example 2 can reach 11.0MPa, the elongation at break is 480%, the water vapor transmission rate of the film is 110g/(m ² ·24h), and the oxygen transmission rate of the film is 3.6cm ³ ·m ^-2 ·24h ^-1 , the antibacterial rate of the antibacterial film can reach more than 99%.

Example 3

1) Synthesis of aqueous polyurethane dispersion:

Add 37.2014g of polytetrahydrofuran and 4.2062g of 2,2-dimethylolpropionic acid to a 500ml round-bottom four-necked flask equipped with a digital display stirrer, temperature control device, and Ar protective gas; adjust the stirring speed to 250r /min, add 75ml of acetone during stirring; after connecting the serpentine condenser tube, wrap the interface with Teflon raw material tape to ensure tightness.

The heating temperature was controlled between 40-50 ℃ by the temperature control device, and heated and stirred for 25min. When the solution in the four-necked flask was colorless and transparent, 0.25ml of catalyst (dibutyltin dilaurate) was added dropwise after 5min. 15.54g of isophorone diisocyanate and an equal amount of acetone were added to the catalyst after 4min; when the temperature in the four-necked flask reached about 70°C, the condenser tube began to condense and reflux, and after 4 hours of condensate reflux, 3.1703g of triethyl ether was then added. amine and an equal amount of acetone; stop heating one hour after adding triethylamine, and when the temperature in the four-necked flask drops below 10°C, remove the condenser tube, connect a constant pressure funnel with 120ml of distilled water, and use Add dropwise at a speed of 6ml/min (adjust the speed of the stirrer to 900r/min before dropping), the solution in the flask will show a phenomenon of thickening and thinning during the dropping process, at this time, adjust the speed of the stirrer to 500r/min. min to prevent the solution from splashing to the inner wall of the flask; wait until the end of the dropwise addition of distilled water in the constant pressure funnel, and then react for 30 min to obtain an aqueous polyurethane dispersion, and pour the aqueous polyurethane dispersion into a silk neck bottle and seal it for storage.

2) Preparation of chlorine dioxide-water-based polyurethane antibacterial film:

Measure 60ml of the aqueous polyurethane dispersion prepared in step 1) with a measuring cylinder, add 8ml of stable chlorine dioxide aqueous solution, stir and mix the two evenly, and pour it into a horizontal square PTFE mold. Naturally air-dried for 36h to form a film to obtain a slow-release chlorine dioxide-water-based polyurethane antibacterial film.

The tensile strength of the antibacterial film prepared in Example 1 can reach 10.1MPa, the elongation at break is about 450%, the water vapor transmission rate of the film is 130g/(m ² ·24h), and the oxygen transmission rate of the film is 5.5 cm ³ ·m ^-2 ·24h ^-1 , the antibacterial rate of the antibacterial film can reach more than 99%.

Comparative Example 1

The difference from Example 3 is that the dropwise addition of distilled water is changed to direct mixing.

After testing, the water vapor transmission rate of the antibacterial film prepared in Comparative Example 1 was 89g/(m ² ·24h), and the oxygen transmission rate of the film was 1.5cm ³ ·m ^-2 ·24h ^-1 . The bacterial rate is above 85%.

Comparative Example 2

The difference from Example 3 is that the amount of acetone added each time is 3 times the amount of polytetrahydrofuran added.

After testing, the water vapor transmission rate of the antibacterial film prepared in Comparative Example 2 was 89g/(m ² ·24h), and the oxygen transmission rate of the film was 1.8cm ³ ·m ^-2 ·24h ^-1 . The bacterial rate is above 88%.

Comparative Example 3

The difference from Example 3 is that the amount of acetone added three times is not equal, and the amount of acetone added each time from the first to the third time is 1, 1.3, and 1.9 times that of polytetrahydrofuran, respectively.

After testing, the water vapor transmission rate of the antibacterial film prepared in Comparative Example 3 was 78g/(m ² ·24h), and the oxygen transmission rate of the film was 2.1cm ³ ·m ^-2 ·24h ^-1 . The bacterial rate is above 80%.

The above-mentioned embodiments are only to describe the preferred mode of the present invention, but not to limit the scope of the present invention. Without departing from the design spirit of the present invention, those of ordinary skill in the art can Variations and improvements should fall within the protection scope determined by the claims of the present invention.

Claims (7)

1. A preparation method of a slow-release chlorine dioxide-waterborne polyurethane antibacterial film is characterized in that a stable chlorine dioxide aqueous solution is added into a waterborne polyurethane dispersion liquid, the mixture is stirred and mixed evenly, the mixture is placed into a mold, and the mold is dried at room temperature to form a film, so that the slow-release chlorine dioxide-waterborne polyurethane antibacterial film is obtained;

the preparation method of the aqueous polyurethane dispersion comprises the following steps:

adding a soft segment and 2, 2-dimethylolpropionic acid in a protective atmosphere, adding acetone under the stirring condition, carrying out first heating, stirring, dropwise adding a catalyst, adding a hard segment and acetone, carrying out condensation reflux, adding triethylamine and acetone, and carrying out second heating;

stopping heating, cooling, dripping distilled water, and reacting to obtain aqueous polyurethane dispersion;

in all raw materials, the total molar ratio of isocyanic acid radical to hydroxyl is 1.4:1, and the molar weight ratio of triethylamine to 2, 2-dimethylolpropionic acid is 1: 1;

when the acetone is added for the first time, the stirring speed under the stirring condition is 150-250r/min, the adding amount of the acetone is 10-200% of the soft segment molar weight, and the amount of the acetone added each time is the same;

the dropping process of the distilled water is carried out under the stirring state, and the cooling is carried out to be below 10 ℃;

before the distilled water is dripped, the stirring speed is 900-1100r/min, the dripping speed is 2-3 s/min, and when the solution system shows the phenomenon of thickening and thinning, the stirring speed is adjusted to 400-600 r/min.

2. The method for preparing the slow-release chlorine dioxide-waterborne polyurethane antibacterial film according to claim 1, wherein the first heating temperature is 40-50 ℃, and the stirring time after heating is 20-30 min.

3. The method for preparing a sustained-release chlorine dioxide-aqueous polyurethane antibacterial film according to claim 1, wherein the solution system is required to be colorless and transparent before the catalyst is added dropwise.

4. The preparation method of the slow-release chlorine dioxide-waterborne polyurethane antibacterial film according to claim 1, wherein the second heating temperature is 40-50 ℃ and the heating time is 1 h.

5. The preparation method of the slow-release chlorine dioxide-waterborne polyurethane antibacterial film according to claim 1, wherein the addition amount of the stable chlorine dioxide aqueous solution is 6-30% of the volume of the waterborne polyurethane dispersion liquid;

the catalyst is dibutyltin dilaurate, and the addition amount of the catalyst is 0.1-0.5% of the total amount of polyurethane.

6. The preparation method of the slow-release chlorine dioxide-waterborne polyurethane antibacterial film according to claim 1, wherein the hard segment is one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate; the soft segment is one or more of polytetrahydrofuran with molecular weight of 1000-3000, polytrimethylene ether glycol, polycaprolactone glycol and polycarbonate glycol.

7. A slow-release chlorine dioxide-waterborne polyurethane antibacterial film prepared by the preparation method of the slow-release chlorine dioxide-waterborne polyurethane antibacterial film as defined in any one of claims 1 to 6.

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