CN110938365A

CN110938365A - A kind of water-based polyurethane antibacterial coating and preparation method thereof

Info

Publication number: CN110938365A
Application number: CN201811117175.5A
Authority: CN
Inventors: 蒋世春; 白若; 刘晓非; 李景庆
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2018-09-25
Filing date: 2018-09-25
Publication date: 2020-03-31

Abstract

The invention discloses a waterborne polyurethane antibacterial coating and a preparation method thereof. After drying to form a film, a polyurethane coating with antibacterial effect can be obtained. The invention overcomes the problem that the coating does not have antibacterial property, and expands the application range of the polyurethane coating.

Description

Waterborne polyurethane antibacterial coating and preparation method thereof

Technical Field

The invention belongs to the technical field of polymer modification, and particularly relates to a waterborne polyurethane antibacterial coating and a preparation method thereof.

Background

Polyurethane can be regarded as a copolymer comprising a soft segment consisting of an oligomeric polyol and a hard segment consisting of a polyisocyanate and a small chain extender. The polyurethane has the advantages of excellent wear resistance, chemical resistance, oil resistance, strong adhesive force, low-temperature curing property, good flexibility, high and low temperature resistance, environmental protection and the like. The polyurethane coating is developed rapidly and widely, and is mainly used as furniture paint, electrophoretic paint, electrodeposition paint, building paint, paper treatment paint, glass fiber paint, metal paint and the like. The polyurethane coating is modified to obtain special coatings suitable for different occasions.

The bacteria have wide range and high reproduction speed, and are easy to breed in kitchens, restaurants, hospitals and various public places, thereby seriously affecting the health of human beings. Therefore, the comprehensive consideration of various sterilization methods is very important for producing materials with antibacterial performance, and the antibacterial coating can well protect the surface of the body and inhibit the growth of bacteria on the surface, and can be widely applied to the fields of medical treatment and health, food safety, furniture mildew prevention and the like. Benzalkonium chloride, also called alkyl dimethyl benzyl chloride, is a cationic surfactant, belongs to a non-oxidative bactericide, has broad-spectrum and high-efficiency sterilization and algae removal capability, and has very wide application in medical disinfection and industrial sterilization. If the polyurethane and the benzalkonium chloride are mixed, the antibacterial property can be increased on the basis of keeping the original excellent performance of the polyurethane, and the application range of the polyurethane coating is expanded.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, modify polyurethane paint and provide the waterborne polyurethane antibacterial paint and the preparation method thereof.

The technical purpose of the invention is realized by the following technical scheme.

An aqueous polyurethane antibacterial coating and a preparation method thereof are carried out according to the following steps:

step 1, uniformly mixing polytetrahydrofuran diol and isophorone diisocyanate, adding a catalyst, and reacting for 1-3 hours at 70-90 ℃, wherein the molar ratio of the polytetrahydrofuran diol to the isophorone diisocyanate is (5-10): (5-13);

in step 1, the molar ratio of polytetrahydrofuran diol to isophorone diisocyanate is 5: (10-13).

In step 1, polytetrahydrofuran polyether glycol is dehydrated in vacuum, and after protective gas is introduced, isophorone diisocyanate is added and mixed uniformly, and inert protective gas such as nitrogen, helium or argon is protected.

In step 1, the reaction is carried out at 80-90 ℃ for 2-3 hours.

In step 1, the catalyst is dibutyltin dilaurate in an amount of 0.1 to 0.5 parts by volume, 1ml each.

Step 2, reducing the system reacted in the step 1 to 45-50 ℃, diluting the prepolymer obtained in the step 1 by using acetone, adding N-methyldiethanolamine into the diluted system, and reacting at 50-70 ℃ for 1-5 hours, wherein the molar ratio of the N-methyldiethanolamine to the polytetrahydrofuran glycol is (5-30) to (5-10), and the amount of the acetone is 20-40% of the mass of the prepolymer;

in step 2, the molar ratio of N-methyldiethanolamine to polytetrahydrofurandiol is (10-20) to (5-10).

In step 2, acetone is used in an amount of 30-40% of the mass of the prepolymer.

In step 2, the reaction is carried out at 50-60 ℃ for 3-5 hours.

Step 3, cooling the system reacted in the step 2 to 40 +/-2 ℃, adding acetone for dilution, and then adding glacial acetic acid with the same mole as that of the N-methyldiethanolamine for neutralization, wherein the acetone dosage is 20-40% of the mass of the system reacted in the step 2

In step 3, the amount of acetone is 30-40% of the mass of the system subjected to the reaction in step 2.

In step 3, glacial acetic acid is added for neutralization for a period of 30 to 60min, preferably 40 to 50 min.

In step 3, after neutralization, the system pH was 7. + -. 0.2.

And 4, dripping the water solution for dissolving and dispersing benzalkonium chloride into the system which is at a high rotating speed and is subjected to the reaction in the step 3 for emulsification, and removing acetone by rotary evaporation after the emulsification is finished to obtain the antibacterial waterborne polyurethane coating, wherein the dosage of the benzalkonium chloride is 0.01-0.5 of the mass of the system which is subjected to the reaction in the step 3.

In step 4, the high rotation speed is 800-.

In step 4, the dosage of benzalkonium chloride is 0.1-0.4 of the mass of the system after the reaction in step 3.

In the technical scheme of the invention, an oil bath is adopted for temperature control, the heating rate is 1-5 ℃/min, and the cooling rate is 1-5 ℃/min.

The polyurethane antibacterial coating disclosed by the invention is reasonable in components, good in stability, smooth and transparent after film forming, good in toughness and high in strength. The antibacterial agent benzalkonium chloride is uniformly dispersed in the coating, is uniformly distributed in the polyurethane after film forming, has antibacterial property, and can kill bacteria attached to the surface.

Drawings

FIG. 1 is a stress-strain graph of an embodiment of the present invention.

FIG. 2 is a test chart of the inhibition zone of Escherichia coli in example 1 of the present invention.

FIG. 3 is a test chart of the inhibition zone of Escherichia coli in example 2 of the present invention.

FIG. 4 is a test chart of the inhibition zone of Staphylococcus aureus in example 2 of the present invention.

FIG. 5 is a schematic diagram of the adhesion test results of example 2 and PVC in the present invention.

Detailed Description

The technical scheme of the invention is further illustrated by combining the examples. Polytetrahydrofuran diol (number average molecular weight 2000), which is a straight-chain polyether diol having hydroxyl groups at both molecular ends, is obtained by cationic ring-opening polymerization of Tetrahydrofuran (THF) in the presence of a catalyst, shanghai alatin biochemical technology ltd; isophorone diisocyanate, Shanghai Allan Biochemical technology Ltd; n-methyldiethanolamine, shanghai chinese bamboo biotechnology limited; glacial acetic acid, wind boat chemical reagents science ltd, Tianjin; acetone, tianjin yueli chemical limited; the apparatus model was TST-350 manufactured by Linkam corporation, the measuring temperature was 25 ℃, the stretching speed was 100 μm/s, and the film sample was cut into a dumbbell shape in which the effective part was 2mmX6 mm. Nitrogen is adopted for inert atmosphere protection, high rotating speed is 1200r/min for emulsification, oil bath is adopted for temperature control, the heating rate is 5 ℃/min, and the cooling rate is 5 ℃/min.

Example 1

0.005mol of polytetrahydrofuran diol is added into a four-neck flask provided with a thermometer and a condenser, vacuum pumping is carried out at 90 ℃ for half an hour for dehydration, the temperature is reduced to 70 ℃, 0.013mol of isophorone diisocyanate and 0.1ml of dibutyltin dilaurate are added, and the reaction is carried out for 3 hours. The temperature is reduced to 50 ℃, 10g of acetone is added to dilute the prepolymer, 0.005mol of N-methyldiethanolamine is added, and the temperature is raised to 70 ℃ for reaction for 5 hours. Cooling to below 50 ℃, adding 5g of acetone, adding 0.005mol of glacial acetic acid at normal temperature, and reacting for half an hour. 35g of deionized water was added dropwise from a constant pressure dropping funnel, and emulsification was carried out at a high stirring rate. Stirring for 10 minutes, and removing the acetone by rotary evaporation to obtain the stable polyurethane coating. The polyurethane is prepared by carrying out prepolymerization on polyether diol and diisocyanate, then carrying out chain extension by a micromolecule chain extender, and neutralizing by acid to obtain the cationic polyurethane. The hard segment of the prepared polyurethane consists of isophorone diisocyanate and a micromolecular chain extender, and the hard segment provides rigidity for the whole molecular chain. The soft segment is composed of polyether polyol to provide flexibility. The polyurethane has good mechanical property due to the hydrogen bond function in the molecular chain. Polyurethane itself has no antibacterial property and does not kill bacteria attached to the surface.

Example 2

0.005mol of polytetrahydrofuran diol is added into a four-neck flask provided with a thermometer and a condenser, vacuum pumping is carried out at 90 ℃ for half an hour for dehydration, the temperature is reduced to 70 ℃, 0.013mol of isophorone diisocyanate and 0.1ml of dibutyltin dilaurate are added, and the reaction is carried out for 3 hours. The temperature is reduced to 50 ℃, 10g of acetone is added to dilute the prepolymer, 0.005mol of N-methyldiethanolamine is added, and the temperature is raised to 70 ℃ for reaction for 5 hours. Cooling to below 50 ℃, adding 5g of acetone, adding 0.005mol of glacial acetic acid at normal temperature, and reacting for half an hour. 0.0027g of benzalkonium chloride, 35g of a prepared aqueous solution, dropwise adding the benzalkonium chloride aqueous solution into a constant-pressure dropping funnel, and emulsifying at a high stirring rate. Stirring for 10 minutes, and removing acetone by rotary evaporation to obtain the stable polyurethane antibacterial coating.

Example 3

0.010mol of polytetrahydrofuran diol is added into a four-neck flask provided with a thermometer and a condenser, vacuum pumping is carried out at 90 ℃ for half an hour for dehydration, the temperature is reduced to 70 ℃, 0.013mol of isophorone diisocyanate and 0.1ml of dibutyltin dilaurate are added, and the reaction is carried out for 3 hours. The temperature is reduced to 45 ℃, 10g of acetone is added to dilute the prepolymer, 0.01mol of N-methyldiethanolamine is added, and the temperature is raised to 70 ℃ for reaction for 5 hours. Cooling to below 50 ℃, adding 5g of acetone, adding 0.005mol of glacial acetic acid at normal temperature, and reacting for 60 min. 0.0027g of benzalkonium chloride, 35g of a prepared aqueous solution, dropwise adding the benzalkonium chloride aqueous solution into a constant-pressure dropping funnel, and emulsifying at a high stirring rate. Stirring for 10 minutes, and removing acetone by rotary evaporation to obtain the stable polyurethane antibacterial coating.

Example 4

0.01mol of polytetrahydrofuran diol is added into a four-neck flask provided with a thermometer and a condenser, vacuum pumping is carried out at 90 ℃ for half an hour for dehydration, the temperature is reduced to 70 ℃, 0.013mol of isophorone diisocyanate and 0.1ml of dibutyltin dilaurate are added, and the reaction is carried out for 3 hours. The temperature is reduced to 50 ℃, 10g of acetone is added to dilute the prepolymer, 0.01mol of N-methyldiethanolamine is added, and the temperature is raised to 70 ℃ for reaction for 5 hours. Cooling to 50 ℃, adding 5g of acetone, adding 0.005mol of glacial acetic acid at normal temperature, and reacting for 40 min. 0.003g of benzalkonium chloride, 35g of a prepared aqueous solution, dropwise adding the benzalkonium chloride aqueous solution into a constant-pressure dropping funnel, and emulsifying at a high stirring rate. Stirring for 10 minutes, and removing acetone by rotary evaporation to obtain the stable polyurethane antibacterial coating.

Example 5

0.01mol of polytetrahydrofuran diol is added into a four-neck flask provided with a thermometer and a condenser, vacuum pumping is carried out at 90 ℃ for half an hour for dehydration, the temperature is reduced to 70 ℃, 0.013mol of isophorone diisocyanate and 0.1ml of dibutyltin dilaurate are added, and the reaction is carried out for 3 hours. The temperature is reduced to 50 ℃, 10g of acetone is added to dilute the prepolymer, 0.02mol of N-methyldiethanolamine is added, and the temperature is raised to 70 ℃ for reaction for 5 hours. Cooling to below 50 ℃, adding 5g of acetone, adding 0.005mol of glacial acetic acid at normal temperature, and reacting for 50 min. 0.0025g of benzalkonium chloride, 35g of a prepared aqueous solution, dropwise adding the benzalkonium chloride aqueous solution into a constant-pressure dropping funnel, and emulsifying at a high stirring rate. Stirring for 10 minutes, and removing acetone by rotary evaporation to obtain the stable polyurethane antibacterial coating.

The polyurethane antibacterial coating prepared by the invention has good adhesive force with a PVC substrate, the coating is coated on a PVC plate, a grid drawing test is carried out after drying, and a coating in a cutting area is perfect, does not peel, does not stick up edges, and does not fall off, as shown in figure 5. The polyurethane antibacterial coating prepared by the invention has good mechanical properties after film forming, as shown in figure 1, and the yield strength reaches 0.33-0.35 MPa, the breaking strength reaches 0.12-0.15 MPa, and the breaking elongation rate reaches 350-370% through mechanical tests, which are determined by the structure of polyurethane. Polytetrahydrofuran diol provides flexibility for a molecular chain, isophorone diisocyanate and a small molecular chain extender provide rigidity for the molecular chain, and hydrogen bonds exist in the molecular chain, so that the strength of polyurethane is increased.

The coatings prepared in examples 1 and 2 were applied to a polytetrafluoroethylene plate and dried at 60 ℃ for 24 hours. Drying, cutting the coating into round pieces with diameter of 1.2mm and thickness of 0.3mm, sterilizing with ultraviolet rays for 3 hours, respectively and uniformly coating Escherichia coli and Staphylococcus aureus on the culture medium, putting the round polyurethane film into the culture medium, culturing for 24 hours, and observing. The polyurethane film without the antibacterial agent benzalkonium chloride has no obvious antibacterial zone, can not kill bacteria attached to the surface, and the polyurethane coating is not antibacterial. The polyurethane film added with benzalkonium chloride has obvious antibacterial zone around, can kill colibacillus and staphylococcus aureus on the surface, and has good antibacterial effect. The antibacterial agent of the waterborne polyurethane prepared by the invention is uniformly distributed, and the emulsion state is stable. The dried coating has excellent antibacterial performance, obvious growth inhibition effect on escherichia coli and staphylococcus aureus, uniform and smooth coating, no wrinkles and shrinkage holes, good adhesion and can be used as an antibacterial coating.

The preparation of antibacterial coatings and coatings can be achieved by adjusting the process parameters according to the content of the invention, and the antibacterial coatings and coatings show performances which are basically consistent with the invention. The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.

Claims

1. a water-based polyurethane antibacterial coating, is characterized in that, carry out according to the following steps:

In step 1, polytetrahydrofuran diol and isophorone diisocyanate are mixed uniformly, and then a catalyst is added, and the reaction is carried out at 70-90 ° C for 1-3 hours, wherein the molar ratio of polytetrahydrofuran diol and isophorone diisocyanate is: (5-10): (5-13);

Step 2, the system reacted in step 1 is lowered to 45-50°C, the prepolymer obtained in step 1 is diluted with acetone, N-methyldiethanolamine is added to the diluted system, and the reaction is performed at 50-70°C 1-5 hours, wherein the mol ratio of N-methyldiethanolamine and polytetrahydrofuran diol is (5-30): (5-10), and the acetone consumption is 20-40% of the prepolymer quality;

In step 3, the system reacted in step 2 is lowered to 40±2°C, acetone is added for dilution, and glacial acetic acid equal to moles of N-methyldiethanolamine is added for neutralization, wherein the amount of acetone is the system reacted in step 2. 20-40% of the quality;

In step 4, the aqueous solution of dissolving and dispersing benzalkonium chloride is dropped into the system reacted in step 3 at a high rotational speed for emulsification, and after the emulsification is completed, the acetone is removed by rotary evaporation to obtain a water-based polyurethane coating with antibacterial properties, wherein benzene The dosage of oxalonium chloride is 0.01-0.5 of the quality of the system reacted in step 3.

2. a kind of water-based polyurethane antibacterial coating according to claim 1, is characterized in that, in step 1, polytetrahydrofuran polyether diol, after vacuum dehydration is passed into protective gas, adds isophorone diisocyanate and mixes homogeneously , protective odor inert protective gas, such as nitrogen, helium or argon; the molar ratio of polytetrahydrofuran diol and isophorone diisocyanate is 5: (10-13); react at 80-90 ° C for 2-3 hour; the catalyst is dibutyltin dilaurate, and the dosage is 0.1-0.5 parts by volume, and each part by volume is 1ml.

3. a kind of water-based polyurethane antibacterial coating according to claim 1 is characterized in that, in step 2, the mol ratio of N-methyldiethanolamine and polytetrahydrofuran diol is (10-20): (5-10 ); the amount of acetone is 30-40% of the mass of the prepolymer; the reaction is carried out at 50-60° C. for 3-5 hours.

4. a kind of water-based polyurethane antibacterial coating according to claim 1, is characterized in that, in step 3, acetone consumption is 30-40% of the system quality reacted through step 2; The time of adding glacial acetic acid for neutralization is 30-60min, preferably 40-50min; after neutralization, the pH of the system is 7±0.2.

5. a kind of water-based polyurethane antibacterial coating according to claim 1 is characterized in that, in step 4, high rotating speed is 800-1200r/min, preferably 800-1000r/min, emulsification time is 10-20min, benzalkonium The dosage of ammonium chloride is 0.1-0.4 of the quality of the system reacted in step 3.

6. a preparation method of water-based polyurethane antibacterial paint, is characterized in that, carry out according to the following steps:

7. The preparation method of a water-based polyurethane antibacterial coating according to claim 6, characterized in that, in step 1, the polytetrahydrofuran polyether diol is vacuum dehydrated and passed into a protective gas, and then isophorone diol is added. The isocyanate is mixed evenly, and the odor is protected by an inert protective gas, such as nitrogen, helium or argon; the molar ratio of polytetrahydrofuran diol and isophorone diisocyanate is 5: (10-13); the reaction is carried out under the condition of 80-90 ℃ 2-3 hours; the catalyst is dibutyltin dilaurate, and the dosage is 0.1-0.5 parts by volume, and each part by volume is 1 ml.

8. the preparation method of a kind of water-based polyurethane antibacterial coating according to claim 6, is characterized in that, in step 2, the mol ratio of N-methyldiethanolamine and polytetrahydrofuran diol is (10-20): ( 5-10); the amount of acetone is 30-40% of the mass of the prepolymer; the reaction is carried out at 50-60° C. for 3-5 hours.

9. The preparation method of a water-based polyurethane antibacterial coating according to claim 6, characterized in that, in step 3, the amount of acetone is 30-40% of the quality of the system reacted in step 2; glacial acetic acid is added for neutralization The time is 30-60min, preferably 40-50min; after neutralization, the pH of the system is 7±0.2.

10. The preparation method of a water-based polyurethane antibacterial coating according to claim 6, wherein in step 4, the high rotational speed is 800-1200r/min, preferably 800-1000r/min, and the emulsification time is 10-20min , the dosage of benzalkonium chloride is 0.1-0.4 of the quality of the system reacted in step 3.