High performance flexible waterproof polyurethane composite coating material

Abstract

The application discloses a high-performance soft waterproof polyurethane composite coating material, and relates to the technical field of polyurethane composite coating material production, which comprises the following raw materials in parts by mass: 30-45 parts of polybutylene adipate glycol, 15-22 parts of isophorone diisocyanate, 3-5 parts of dimethylol propionic acid, 5-10 parts of polycaprolactone glycol, 1-3 parts of 1,4-butanediol, 20-35 parts of acetone, 2-3.5 parts of triethylamine and 18-24 parts of neutralization intermediate. The neutralization intermediate is added in the raw materials, the biocompatibility of chitosan and the film-forming property of polyvinyl alcohol are utilized, the neutralization intermediate is finely dispersed through ultrasonic treatment, and then is combined with the polyurethane emulsion, so that the prepared composite coating material has good blood coagulation promoting effect, blood pollution can be effectively avoided, the composite coating material is suitable for medical bed sheets, bed pads and other scenes, and the medical functionality of the material is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurethane composite coating material production, in particular to a high-performance soft waterproof polyurethane composite coating material. BACKGROUND

[0002] Polyurethane composite coating material refers to a coating material with specific functions and properties formed by combining polyurethane with other materials, which combines the advantages of polyurethane itself and the characteristics of other materials to meet various requirements for coating performance in different fields. In the medical field, polyurethane composite coating material is often used in the preparation of bed sheets and mattresses.

[0003] Existing waterproof coating materials, such as conventional polyurethane coatings, can block liquid penetration, but lack the function of promoting blood clotting, and cannot quickly control blood spread in the event of accidental bleeding. At the same time, the effective components of existing medical coating materials are uniformly distributed, and after repeated washing and sunlight exposure, the surface effective components are easily lost, leading to rapid functional decay and shortened service life. To maintain performance, the product needs to be frequently replaced, which has the problem of low practicality and functionality.

[0004] In view of the problems in the related art, no effective solution has been proposed so far. SUMMARY

[0005] In view of the problems in the related art, the present application proposes a high-performance soft waterproof polyurethane composite coating material to overcome the above technical problems existing in the prior art.

[0006] To this end, the specific technical solutions adopted by the present application are as follows:

[0007] A high-performance soft waterproof polyurethane composite coating material, comprising the following mass fractions of raw materials: wherein the raw materials are composed of 30-45 parts of polyhexanedioic acid-1, 4-butanediol glycol, 15-22 parts of isophorone diisocyanate, 3-5 parts of dimethylol propionic acid, 5-10 parts of polycaprolactone glycol, 1-3 parts of 1, 4-butanediol, 20-35 parts of acetone, 2-3.5 parts of triethylamine, and 18-24 parts of neutralization intermediate;

[0008] The neutralization intermediate is made by the following steps:

[0009] Step 1, add chitosan and deionized water containing 1% acetic acid into a glass-lined reaction kettle, stir until a transparent solution is obtained, then add deionized water and polyvinyl alcohol, and dissolve into a glue solution at 95℃ high temperature;

[0010] Step 2, anhydrous calcium chloride powder is slowly added to deionized water at room temperature, and stirred at a speed of 300 rpm until completely dissolved to prepare a 30% calcium chloride aqueous solution, and the glue solution is cooled to 60℃, then the calcium chloride aqueous solution is slowly added dropwise, and after the dropwise addition is completed, continue to heat and stir for 30 minutes, and then put into an ultrasonic tank for fine dispersion to obtain a neutralization intermediate.

[0011] As a preferred embodiment, the mass ratio of chitosan, 1% acetic acid-containing deionized water, deionized water and polyvinyl alcohol used in step 1 is 3:4:5:2, the temperature of the glass-lined reactor in step 1 is set to 55℃ when stirring to a transparent solution, the stirring speed is 150 rpm, and the stirring time is 90 minutes. The stirring speed is 200 rpm when dissolving into a glue solution at high temperature, and the stirring time is 120 minutes.

[0012] As a preferred embodiment, the stirring device in step 2 is heated and stirred at a speed of 300 rpm, the ultrasonic tank has an ultrasonic power of 500W, and the duration is 120 minutes, wherein the mass ratio of chitosan to calcium chloride aqueous solution is 1:0.9.

[0013] A preparation method of a high-performance soft waterproof polyurethane composite coating material, comprising the following preparation steps:

[0014] S1, the following raw materials are weighed according to the mass fraction: wherein the raw materials are composed of 30-45 parts of polyhexanedioic acid-1, 4-butanediol glycol, 15-22 parts of isophorone diisocyanate, 3-5 parts of dimethylol propionic acid, 5-10 parts of polycaprolactone glycol, 1-3 parts of 1, 4-butanediol, 20-35 parts of acetone, 2-3.5 parts of triethylamine, and 18-24 parts of neutralization intermediate;

[0015] S2, the polyhexanedioic acid-1, 4-butanediol glycol and the polycaprolactone glycol are pre-mixed and then added to the first temperature zone of the co-rotating twin-screw extruder for vacuum dehydration, and the dehydrated material is sent to the second and third temperature zones, and isophorone diisocyanate is injected, and the stirring reaction is carried out for 2-3 hours to obtain a prepolymer;

[0016] S3, the dimethylol propionic acid, 1, 4-butanediol and 60% of the total amount of acetone are pre-mixed to form a homogeneous solution, the prepolymer is added to a static mixer and the homogeneous solution is injected simultaneously, and the reaction is carried out for 1-2 hours, and the remaining 40% of the acetone is used to adjust to the target viscosity to obtain a mixture;

[0017] S4, the mixture is placed in a stirring device, triethylamine is added for neutralization reaction for 0.5-1 hour, the pH is adjusted to 7.5-8.0, and after the reaction is completed, it is placed in a high-speed shearing emulsifier, deionized water is slowly added, and emulsified at 5000 rpm for 20 minutes to obtain a polyurethane emulsion;

[0018] S5, coating the material liquid on the substrate through the microfluidic coating head, forming a gradient structure through interlayer hot air curing, the material liquid being a mixed liquid of polyurethane emulsion and neutralization intermediate, including bottom layer material liquid, middle layer material liquid and surface layer material liquid, after coating, placing in a vacuum drying machine to remove acetone at 60 DEG C vacuum drying, winding, cutting and packaging.

[0019] As a preferred embodiment, in S2, the temperature and pressure of the first temperature zone are 60 DEG C and -0.08 MPa respectively, the vacuum dehydration time is 1-2 hours, and the temperature of the second and third temperature zones is set to 83-87 DEG C under normal pressure, and the screw rotation speed is 200 rpm.

[0020] As a preferred embodiment, in S3, the temperature of the prepolymer added into the static mixer and the miscible solution is set to 70 DEG C, the pressure is 0.5 MPa, and the target viscosity is 1700 cP.

[0021] As a preferred embodiment, in S4, the mass ratio of triethylamine to deionized water is 1:35, the rotation speed of the neutralization reaction is set to 300 rpm, and the reaction temperature is 30-40 DEG C.

[0022] As a preferred embodiment, in S5, the coating parameters of the microfluidic coating head are 1.5 m / min, the thickness of each layer is set to 0.05 mm, the interlayer hot air drying is 70 DEG C for 60 s, and the mass ratio of the neutralization intermediate in the bottom layer material liquid, the middle layer material liquid and the surface layer material liquid is 3:2:1.

[0023] The present application has the following advantages:

[0024] 1. By adding a neutralization intermediate to the raw material, the prepared composite coating material has good blood coagulation promoting effect, can effectively prevent blood from spreading and polluting, is suitable for medical bed sheets, mattress and other scenes, and improves the medical functionality of the material.

[0025] 2. The gradient coating design is adopted, the content of the neutralization intermediate in the bottom layer, the middle layer and the surface layer material liquid decreases in turn, the effective component forms a concentration gradient distribution in the coating, and in the process of sunlight exposure after cleaning, the effective component is promoted to diffuse from the high concentration area to the low concentration area and migrate to the surface of the coating, thereby prolonging the effective service life of the material.

[0026] 3. The raw materials such as polyhexanedioic acid-1, 4-butanediol glycol and polycaprolactone diol are effectively combined with the neutralization intermediate through the steps of prepolymer preparation, neutralization reaction and high-speed shear emulsification, so that the material has a high water contact angle and excellent waterproof performance. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0028] Figure 1 is a flow chart of a preparation method of a high-performance soft waterproof polyurethane composite coating material according to an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to further illustrate the embodiments, the present application provides accompanying drawings which are part of the disclosure of the present application, mainly used to illustrate the embodiments, and can be used to explain the operating principle of the embodiments in conjunction with the related description of the specification. Those skilled in the art should be able to understand other possible embodiments and advantages of the present application by referring to these contents. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0030] According to an embodiment of the present application, a high-performance soft waterproof polyurethane composite coating material is provided.

[0031] The present application will be further described in conjunction with the accompanying drawings and specific embodiments:

[0032] Embodiment 1

[0033] The high-performance soft waterproof polyurethane composite coating material according to an embodiment of the present application comprises the following mass fractions of raw materials: wherein the raw materials are composed of 30-45 parts of polyhexanedioic acid-1, 4-butanediol glycol, 15-22 parts of isophorone diisocyanate, 3-5 parts of dimethylol propionic acid, 5-10 parts of polycaprolactone glycol, 1-3 parts of 1, 4-butanediol, 20-35 parts of acetone, 2-3.5 parts of triethylamine, and 18-24 parts of a neutralization intermediate;

[0034] The neutralization intermediate is made by the following steps:

[0035] Step 1, chitosan and deionized water containing 1% acetic acid are added to a glass-lined reaction kettle, stirred to a transparent solution, then deionized water is added and polyvinyl alcohol is added, and the solution is dissolved into a glue solution at 95°C high temperature;

[0036] Step 2, anhydrous calcium chloride powder is slowly added to deionized water at room temperature, stirred at a speed of 300 rpm until completely dissolved, to prepare a 30% calcium chloride aqueous solution, the glue solution is cooled to 60°C, then the calcium chloride aqueous solution is slowly added dropwise, and after the dropwise addition is completed, the temperature is continued to be kept and stirred for 30 minutes, then it is placed in an ultrasonic tank for fine dispersion to obtain the neutralization intermediate;

[0037] The mass ratio of chitosan, deionized water containing 1% acetic acid, deionized water, and polyvinyl alcohol used in step 1 is 3:4:5:2, the temperature of the glass-lined reactor in step 1 is set to 55°C when stirring to a transparent solution, the stirring speed is 150 rpm, the stirring time is 90 minutes, and the stirring speed during high-temperature dissolution into a glue solution is 200 rpm, and the stirring time is 120 minutes;

[0038] The stirring device in step 2 is kept at a stirring speed of 300 rpm, and the ultrasonic tank is kept at an ultrasonic power of 500 W for a duration of 120 minutes, wherein the mass ratio of chitosan to calcium chloride aqueous solution is 1:0.9;

[0039] A preparation method of a high-performance soft waterproof polyurethane composite coating material, comprising the following preparation steps:

[0040] S1, the following raw materials are weighed according to mass fraction: wherein the raw materials are composed of 30-45 parts of polybutylene adipate glycol, 15-22 parts of isophorone diisocyanate, 3-5 parts of dimethylol propionic acid, 5-10 parts of polycaprolactone glycol, 1-3 parts of 1, 4-butanediol, 20-35 parts of acetone, 2-3.5 parts of triethylamine, and 18-24 parts of neutral intermediate;

[0041] S2, the polybutylene adipate glycol and the polycaprolactone glycol are pre-mixed and then added to the first temperature zone of a co-rotating twin-screw reaction extruder for vacuum dehydration, and the dehydrated material is sent to the second and third temperature zones, isophorone diisocyanate is injected, and stirring is performed for 2-3 hours to obtain a prepolymer;

[0042] S3, the dimethylol propionic acid, 1, 4-butanediol, and 60% of the total amount of acetone are pre-mixed to form a homogeneous solution, the prepolymer is added to a static mixer and the homogeneous solution is injected simultaneously, and the mixture is reacted for 1-2 hours, and the remaining 40% of the acetone is used to adjust the target viscosity to obtain a mixture;

[0043] S4, the mixture is placed in a stirring device, triethylamine is added for neutralization reaction for 0.5-1 hour, the pH is adjusted to 7.5-8.0, and after the reaction is completed, the mixture is placed in a high-speed shearing emulsifier, deionized water is slowly added, and emulsification is performed at 5000 rpm for 20 minutes to obtain a polyurethane emulsion;

[0044] S5, the liquid is coated on the substrate through a microfluidic coating head, a gradient structure is formed by interlayer hot air curing, the liquid is a mixture of polyurethane emulsion and neutral intermediate, including a bottom layer liquid, a middle layer liquid, and a surface layer liquid, and after coating is completed, the material is placed in a vacuum drying machine for vacuum drying at 60°C to remove acetone, and then it is wound, cut, and packaged;

[0045] The parameter of the temperature zone one in S2 is 60℃, -0.08MPa, the vacuum dehydration time is 1-2 hours, the temperature of the temperature zone two and three is set to 83-87℃ under normal pressure, the screw rotation speed is 200rpm, the temperature in S3 is set to 70℃, the pressure is 0.5MPa when the prepolymer is added into the static mixer and the homogeneous solution is injected synchronously, the target viscosity is 1700cP, the mass ratio of triethylamine to deionized water in S4 is 1:35, the rotation speed of the neutralization reaction is set to 300rpm, the reaction temperature is 30-40℃, the coating parameters of the microfluidic coating head in S5 are 1.5m / min, the thickness of each layer is set to 0.05mm, the interlayer hot air drying is 70℃ drying for 60s, and the mass ratio of the neutralization intermediates in the bottom layer solution, the middle layer solution and the surface layer solution is 3:2:1.

[0046] Example 2:

[0047] A high-performance soft waterproof polyurethane composite coating material, the specific process and preparation process are as follows:

[0048] The first step is to take the following raw materials by mass fraction: wherein the raw materials are composed of 30 parts of polybutylene adipate glycol, 15 parts of isophorone diisocyanate, 3 parts of dimethylol propionic acid, 5 parts of polycaprolactone glycol, 1 part of 1, 4-butanediol, 20 parts of acetone, 2 parts of triethylamine, and 18 parts of neutralization intermediate;

[0049] The second step is to mix 30 parts of polybutylene adipate glycol with 5 parts of polycaprolactone glycol, and then add them into the temperature zone one of the co-rotating twin-screw extruder for vacuum dehydration at 60℃, -0.08MPa for 1-2 hours. Then, add the dehydrated material into the temperature zone two and three, and inject 15 parts of isophorone diisocyanate. Stir and react under 83-87℃ normal pressure and 200rpm screw rotation speed for 2-3 hours to obtain a prepolymer.

[0050] The third step is to mix 3 parts of dimethylol propionic acid, 1 part of 1, 4-butanediol, and 12 parts of acetone to form a homogeneous solution. Then, add the prepolymer into the static mixer and inject the homogeneous solution synchronously. React at 70℃ and 0.5MPa for 1-2 hours. Adjust the target viscosity to 1700cP by adding the remaining 8 parts of acetone, and obtain a mixed material.

[0051] The fourth step is to put the mixed material into a stirring device, add 2 parts of triethylamine, and adjust the pH to 7.5-8.0 by stirring at 300rpm and 30-40℃ for 0.5-1 hours. After the reaction is completed, put it into a high-speed shearing emulsifier, slowly add deionized water, and emulsify for 20 minutes at 5000rpm to obtain a polyurethane emulsion. The mass ratio of triethylamine to deionized water is 1:35.

[0052] The fifth step is to coat the material liquid on the substrate by the microfluidic coating head at a coating speed of 1.5 m / min, a thickness of each layer of 0.05 mm, and interlayer hot air drying at 70℃ / 60s, and form a gradient structure by interlayer hot air curing. The material liquid is a mixture of polyurethane emulsion and neutralized intermediate. The bottom layer material liquid is polyurethane emulsion + 9 parts of neutralized intermediate, the middle layer material liquid is polyurethane emulsion + 6 parts of neutralized intermediate, and the surface layer material liquid is polyurethane emulsion + 3 parts of neutralized intermediate. After coating, it is placed in a vacuum drying machine to remove acetone at 60℃, and then wound, cut and packaged.

[0053] The preparation process of the neutralized intermediate is as follows:

[0054] Step 1: Put chitosan and deionized water containing 1% acetic acid into a glass-lined reaction kettle, stir at 55℃ and 150rpm for 90 minutes to form a transparent solution, then add deionized water and polyvinyl alcohol, and stir at 95℃ and 200rpm for 120 minutes to form a glue solution;

[0055] Step 2: Slowly add anhydrous calcium chloride powder to deionized water at room temperature, stir at 300rpm until completely dissolved to form a 30% calcium chloride aqueous solution. Slowly add the calcium chloride aqueous solution to the glue solution at 60℃, and stir at 300rpm for 30 minutes after adding. Then put it into an ultrasonic tank and disperse at an ultrasonic power of 500W for 120 minutes to obtain the neutralized intermediate.

[0056] In step 1, the mass ratio of chitosan, deionized water containing 1% acetic acid, deionized water, polyvinyl alcohol, and calcium chloride aqueous solution is 3:4:5:2:2.7. The degree of deacetylation of chitosan is ≥90%.

[0057] Example 3:

[0058] A high-performance soft waterproof polyurethane composite coating material, the specific process and preparation process are as follows:

[0059] First, the following raw materials are weighed by mass fraction: 45 parts of polybutylene adipate glycol, 22 parts of isophorone diisocyanate, 5 parts of dimethylol propionic acid, 10 parts of polycaprolactone glycol, 3 parts of 1,4-butanediol, 35 parts of acetone, 3.5 parts of triethylamine, and 24 parts of neutralized intermediate.

[0060] Second step, 45 parts of polybutylene adipate glycol and 10 parts of polycaprolactone glycol are premixed and then added to the temperature zone one of the co-rotating twin screw extruder, vacuum dehydration is carried out at 60℃ and -0.08MPa vacuum for 1-2 hours, the dehydrated material is added to temperature zones two and three, 22 parts of isophorone diisocyanate is injected, and stirring reaction is carried out at 83-87℃ and normal pressure and screw speed of 200rpm for 2-3 hours to obtain a prepolymer;

[0061] Third step, 5 parts of dimethylol propionic acid, 3 parts of 1, 4-butanediol and 21 parts of acetone are premixed to form a homogeneous solution, the prepolymer is added to a static mixer and the homogeneous solution is injected synchronously, reaction is carried out at a temperature of 70℃ and a pressure of 0.5MPa for 1-2 hours, the target viscosity is adjusted to 1700cP by the remaining 14 parts of acetone, and a mixed material is obtained;

[0062] Fourth step, the mixed material is placed in a stirring device, 3.5 parts of triethylamine is added at a reaction temperature of 30-40℃ and a stirring speed of 300rpm, the neutralization reaction time is 0.5-1 hour, the pH is adjusted to 7.5-8.0, after the reaction is completed, it is placed in a high-speed shearing emulsifier, deionized water is slowly added and emulsified at a speed of 5000rpm for 20 minutes, a polyurethane emulsion is obtained, and the mass ratio of triethylamine to deionized water is 1:35;

[0063] Fifth step, the material liquid is coated on the substrate by a microfluidic coating head at a coating speed of 1.5m / min, a thickness of each layer of 0.05mm and interlayer hot air drying at 70℃ / 60s, a gradient structure is formed by interlayer hot air curing, the material liquid is a mixture of polyurethane emulsion and neutralization intermediate, the bottom layer material liquid is polyurethane emulsion+12 parts of neutralization intermediate, the middle layer material liquid is polyurethane emulsion+8 parts of neutralization intermediate, and the surface layer material liquid is polyurethane emulsion+4 parts of neutralization intermediate, after coating is completed, it is placed in a vacuum drying machine to remove acetone at 60℃, and is wound, cut and packaged.

[0064] The preparation process of the neutralization intermediate is as follows:

[0065] Step 1, chitosan and deionized water containing 1% acetic acid are added to a glass-lined reaction kettle, and a transparent solution is obtained after stirring at 55℃ and 150rpm for 90 minutes, then deionized water is injected and polyvinyl alcohol is added, and a glue solution is obtained after stirring at 95℃ and 200rpm for 120 minutes;

[0066] Step 2, anhydrous calcium chloride powder is slowly added to deionized water at room temperature, and stirred at a speed of 300rpm until completely dissolved to prepare a calcium chloride aqueous solution with a concentration of 30%, the glue solution is cooled to 60℃, and the calcium chloride aqueous solution is slowly added dropwise, after the addition is completed, it is stirred at 300rpm for 30 minutes, and then placed in an ultrasonic tank for fine dispersion at an ultrasonic power of 500W for 120 minutes to obtain a neutralization intermediate.

[0067] The mass ratio of chitosan, deionized water containing 1% acetic acid, deionized water, polyvinyl alcohol, and calcium chloride aqueous solution used in step 1 is 3:4:5:2:2.7, and the degree of deacetylation of chitosan is ≥90%.

[0068] Comparative Example 1:

[0069] The “neutralized intermediate” in Example 2 is removed, and the remaining raw materials remain unchanged, and coating is performed on the substrate;

[0070] Comparative Example 2:

[0071] The “neutralized intermediate” in Example 3 is removed, and the remaining raw materials remain unchanged, and coating is performed on the substrate;

[0072] Comparative Example 3:

[0073] In Example 3, the fifth step is changed to single-layer coating, and the liquid is a mixture of polyurethane emulsion and 24 parts of neutralized intermediate

[0074] Experimental Example 1:

[0075] The high-performance soft waterproof polyurethane composite coating materials obtained in Examples 2, 3 and Comparative Examples 1 and 2 are tested for performance, including waterproof performance testing, blood clotting time testing, and effective component analysis testing, and the test results are shown in Table 1:

[0076] Table 1: Performance Test Table of High-Performance Soft Waterproof Polyurethane Composite Coating Material

[0077]

[0078] The water contact angle test is performed on the high-performance soft waterproof polyurethane composite coating materials prepared in Examples 2, 3 and Comparative Examples 1 and 2, a sample of about 2 cm x 2 cm is cut, 5 μL of deionized water is added dropwise, and the static angle is measured after standing for 30 s, and the water contact angle is obtained by repeating the experiment 5 times and taking the average value;

[0079] The blood clotting time test is performed on the high-performance soft waterproof polyurethane composite coating materials prepared in Examples 2, 3 and Comparative Examples 1 and 2, a sample of about 2 cm x 2 cm is cut, and placed in 37°C simulated wound containing 0.2% heparin anticoagulant human plasma, and the time from liquid to gel is recorded, and each group of samples is tested 9 times, and the average value is taken after removing outliers;

[0080] The high-performance soft waterproof polyurethane composite coating material prepared from Examples 2, 3 and Comparative Example 3 was tested. A sample of about 100 cm x 100 cm was cut from the material, washed and placed in a 60 DEG C oven for 4 h to simulate sun exposure. After 5 repeated washing processes, a sample of about 2 cm x 2 cm was cut, placed in 0.2% heparin anticoagulant human plasma at 37 DEG C to simulate a wound, and the time for the plasma to change from liquid to gel was recorded. Each sample was tested 9 times, and the mean value was obtained after removing outliers.

[0081] As can be seen, the water contact angles of Examples 2, 3, Comparative Example 1 and Comparative Example 2 are all between 151 DEG and 155 DEG, indicating that these materials all have excellent waterproof properties, and the water contact angles of the samples are not significantly different, indicating that the neutralization intermediate has little effect on the waterproof properties of the material. After adding the neutralization intermediate, the high-performance soft waterproof polyurethane composite coating material prepared has good blood coagulation promotion effect, which is convenient for application in medical bed sheets and mattress to avoid blood contamination. Based on the gradient coating design, the concentration of the effective component in the coating shows a gradient distribution, i.e. high concentration in the inside and low concentration on the surface. Therefore, the effective component spontaneously diffuses from the high concentration area to the low concentration area, i.e. migrates to the surface of the coating, thereby prolonging the service life.

[0082] In summary, by adding the neutralization intermediate to the raw material, using the biocompatibility of chitosan and the film-forming property of polyvinyl alcohol, and combining with the polyurethane emulsion after ultrasonic refinement and dispersion, the prepared composite coating material has good blood coagulation promotion effect, can effectively prevent blood contamination, is suitable for medical bed sheets, mattress and other scenarios, and improves the medical functionality of the material. By adopting the gradient coating design, the content of the neutralization intermediate in the bottom layer, middle layer and surface layer decreases in turn, so that the effective component forms a concentration gradient distribution in the coating. During the sun exposure process after washing, the effective component diffuses from the high concentration area to the low concentration area and migrates to the surface of the coating due to the concentration difference, thereby prolonging the effective service life of the material. By the steps of prepolymer preparation, neutralization reaction, high-speed shearing emulsification and the like, the polyhexanedioic acid-1, 4-butanediol glycol, polyhexanone glycol and other raw materials are effectively combined with the neutralization intermediate, so that the material has a high water contact angle and excellent waterproof properties.

[0083] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-performance, flexible, waterproof polyurethane composite coating material, characterized in that, The raw materials include the following parts by weight: 30-45 parts of poly(1,4-butanediol adipate), 15-22 parts of isophorone diisocyanate, 3-5 parts of dimethylolpropionic acid, 5-10 parts of polycaprolactone diol, 1-3 parts of 1,4-butanediol, 20-35 parts of acetone, 2-3.5 parts of triethylamine, and 18-24 parts of neutralization intermediate; The neutralizing intermediate is prepared by the following steps: Step 1: Add chitosan and deionized water containing 1% acetic acid to a glass-lined reactor and stir until a transparent solution is obtained. Then, add deionized water and polyvinyl alcohol and dissolve at 95°C to form a gel. Step 2: Slowly add anhydrous calcium chloride powder to room temperature deionized water and stir at 300 rpm until completely dissolved to prepare a 30% calcium chloride aqueous solution. After cooling the gel to 60°C, slowly add the calcium chloride aqueous solution dropwise. After the addition is complete, continue to keep warm and stir for 30 minutes. Then place it in an ultrasonic tank to refine and disperse, and obtain a neutralized intermediate. The composite coating material includes a bottom layer liquid, a middle layer liquid, and a top layer liquid. The bottom layer liquid, the middle layer liquid, and the top layer liquid are mixtures of polyurethane emulsion and neutralizing intermediate. The polyurethane emulsion is prepared from the raw materials except for the neutralizing intermediate. The mass ratio of chitosan, deionized water containing 1% acetic acid, deionized water, and polyvinyl alcohol used in step 1 is 3:4:5:

2. The mass ratio of chitosan to calcium chloride aqueous solution is 1:0.9, and the mass ratio of neutralizing intermediate in the bottom layer solution, middle layer solution and surface layer solution is 3:2:

1.

2. The high-performance, flexible, waterproof polyurethane composite coating material according to claim 1, characterized in that, In step 1, the temperature of the glass-lined reactor when stirring to form a transparent solution is set at 55°C, the stirring speed is 150 rpm, and the stirring time is 90 minutes. When dissolving into a gel at high temperature, the stirring speed is 200 rpm and the stirring time is 120 minutes.

3. The high-performance, flexible, waterproof polyurethane composite coating material according to claim 1, characterized in that, In step 2, the stirring device is kept warm and the stirring speed is 300 rpm, the ultrasonic power of the ultrasonic tank is 500W, and the duration is 120 minutes.

4. A method for preparing a high-performance, flexible, waterproof polyurethane composite coating material as described in any one of claims 1-3, characterized in that, The preparation steps include the following: S1. Weigh the following raw materials according to the following mass percentages: the raw materials consist of 30-45 parts of poly(1,4-butanediol adipate), 15-22 parts of isophorone diisocyanate, 3-5 parts of dimethylolpropionic acid, 5-10 parts of polycaprolactone diol, 1-3 parts of 1,4-butanediol, 20-35 parts of acetone, 2-3.5 parts of triethylamine, and 18-24 parts of neutralization intermediate; S2. Poly(1,4-butanediol adipate) diol and polycaprolactone diol are premixed and added to temperature zone one of the co-rotating twin-screw reactive extruder for vacuum dehydration. The dehydrated material is then fed into temperature zones two and three, and isophorone diisocyanate is injected. The mixture is stirred and reacted for 2-3 hours to obtain the prepolymer. S3. Premix dimethylolpropionic acid, 1,4-butanediol and 60% of the total amount of acetone to form a homogeneous solution. Add the prepolymer to a static mixer and simultaneously inject the homogeneous solution to react for 1-2 hours. Adjust the viscosity to the target using the remaining 40% of acetone to obtain the mixture. S4. Place the mixture into a stirring device, add triethylamine to neutralize the reaction time for 0.5-1 hour, adjust the pH to 7.5-8.0, and after the reaction is complete, place it into a high-speed shear emulsifier, slowly add deionized water and emulsify at 5000 rpm for 20 minutes to obtain a polyurethane emulsion. S5. The liquid is applied to the substrate through a microfluidic coating head and cured by interlayer hot air to form a gradient structure. The liquid is a mixture of polyurethane emulsion and neutralizing intermediate, including bottom layer liquid, middle layer liquid and top layer liquid. After coating, it is placed in a vacuum dryer and dried at 60°C to remove acetone. Then it is rolled up, slit and packaged.

5. The method for preparing a high-performance, flexible, waterproof polyurethane composite coating material according to claim 4, characterized in that, The parameters of temperature zone one in S2 are 60℃ and -0.08MPa, the vacuum dehydration time is 1-2 hours, the temperature of temperature zones two and three are set at 83-87℃ and atmospheric pressure, and the screw speed is 200rpm.

6. The method for preparing a high-performance, flexible, waterproof polyurethane composite coating material according to claim 4, characterized in that, In step S3, when the prepolymer is added to the static mixer and the homogenized solution is injected simultaneously, the temperature is set to 70°C, the pressure to 0.5 MPa, and the target viscosity to be 1700 cP.

7. The high-performance, flexible, waterproof polyurethane composite coating material according to claim 4, characterized in that, In the S4 reaction, the mass ratio of triethylamine to deionized water is 1:35, the rotation speed of the neutralization reaction is set to 300 rpm, and the reaction temperature is 30-40℃.

8. The method for preparing a high-performance, flexible, waterproof polyurethane composite coating material according to claim 4, characterized in that, The coating parameters of the S5 microfluidic coating head are 1.5 m / min, the thickness of each layer is set to 0.05 mm, and the interlayer hot air drying is 70°C for 60 s.

Images