CN102851987A - Hyperbranched waterborne polyurethane coating agent - Google Patents

Abstract

The invention relates to a hyperbranched waterborne polyurethane coating agent, belonging to the technical field of textile chemicals. The present invention synthesizes a kind of hyperbranched waterborne polyurethane (AWHBPU) with terminal hydroxyl blocked by the method of blocking terminal hydroxyl, and by selecting suitable raw materials, proportions and reaction conditions, thereby avoiding the crosslinking problem caused by terminal hydroxyl, and containing AWHBPU The waterborne polyurethane coating agent AWHBPU-PU not only has the advantages of good stability, low viscosity and high solid content, but also improves the flexibility of the polyurethane coating. The water-based polyurethane fabric coating agent provided by the invention can be widely used in the field of fabrics for human body.

Description

A kind of hyperbranched waterborne polyurethane coating agent

technical field

The invention relates to a hyperbranched waterborne polyurethane coating agent, belonging to the technical field of textile chemicals.

Background technique

Water-based polyurethane refers to a type of polyurethane that can be dissolved in water or evenly dispersed in water. It has the good comprehensive properties of solvent-based polyurethane, and because water is used as the dispersion medium, compared with solvent-based polyurethane, it is cheaper and safer to use. Environmental pollution, widely used in textile finishing, leather finishing and other industries, is a new type of polyurethane material that is environmentally friendly and has very good application prospects.

Hyperbranched polymers have structures and properties similar to those of dendritic polymers, with a large number of cavities, branch points, and approximately spherical structures, and their preparation steps are simple without purification, and have recently received extensive attention. The application of hyperbranched polymers in the field of waterborne polyurethane can improve the mechanical properties and processing properties of waterborne polyurethane, so it has received more and more attention.

Although hyperbranched polyurethanes have been synthesized by various methods in recent years, there are still some deficiencies. Chinese patent CN1385451 and CN1385450 generate AB _n monomer with diisocyanate (A ₂ monomer) and monoaminopolyol (bB _n monomer) reaction, and AB _n monomer just synthesizes hyperbranched polyurethane by self condensation; Chinese patent CN101074278 Hyperbranched polyurethanes were synthesized from diisocyanate (A ₂ monomer) and triol (B ₃ monomer). Because -NCO is very easy to react with water in the air and is not easy to store, the end groups of these hyperbranched waterborne polyurethanes are designed to be terminal hydroxyl groups. At the same time, because they do not contain hydrophilic groups, these hyperbranched polyurethanes can only be used as crosslinking agents, resulting in The emulsion has high viscosity and is not easy to disperse, and the resulting coating generally has poor flexibility. Chinese patent CN 101440150A discloses a hyperbranched water-based polyurethane. Due to its hydrophilic carboxyl ions, this kind of hyperbranched polyurethane itself can be dispersed in water, but because it is still used as a crosslinking agent, it is used in water-based polyurethane coating agents At this time, a large number of terminal hydroxyl groups of this kind of hyperbranched waterborne polyurethane cause emulsion crosslinking, resulting in an increase in emulsion viscosity, which cannot overcome the problems of high solvent usage and low solid content, and its coating has poor flexibility.

Contents of the invention

The purpose of the present invention is to provide a kind of hyperbranched waterborne polyurethane coating agent in order to solve the shortcomings of traditional hyperbranched waterborne polyurethane coating agent such as poor stability, high viscosity, low solid content and poor coating flexibility. The present invention synthesizes a kind of hyperbranched water-based polyurethane (AWHBPU) with terminal hydroxyl blocked by the method of blocking terminal hydroxyl, and by selecting suitable raw materials, ratios and reaction conditions, thereby avoiding the cross-linking problem caused by terminal hydroxyl, containing AWHBPU The water-based polyurethane coating agent (AWHBPU-PU) not only has the advantages of good stability, low viscosity and high solid content, but also improves the flexibility of polyurethane coating at the same time.

The purpose of the present invention is achieved through the following technical solutions:

The present invention uses isophorone diisocyanate, dimethylol propionic acid and diethanolamine as raw materials to synthesize hyperbranched water-based polyurethane (WHBPU), uses acetic anhydride to seal the hydroxyl group of WHBPU, and synthesizes and prepares acetyl-blocked hyperbranched Aqueous polyurethane (AWHBPU), and blend AWHBPU into aqueous polyurethane emulsion, obtain hyperbranched aqueous polyurethane blending modified polyurethane coating agent (AWHBPU-PU). The coating agent has good stability, low viscosity and high solid content, and has good mechanical properties after film formation.

A kind of hyperbranched aqueous polyurethane coating agent of the present invention, the concrete preparation steps of this coating agent are as follows:

Step 1) Synthesis of WHBPU

①Dissolve dimethylolpropionic acid (DMPA) in N,N-dimethylformamide (DMF) at a mass ratio of 1:4~5, and then add the mixture dropwise to the isofor at 50~80°C In ketone diisocyanate (IPDI), react for 5-15 hours;

②Reduce the temperature of the above reaction solution to -25~0°C, add diethanolamine (DEOA) dropwise to the reaction solution, and react for 2~6 hours after the dropwise addition;

③The temperature of the above reaction solution is raised to 80-110°C, and dibutyltin dilaurate or stannous octoate is added dropwise to the reaction system according to the ratio of 0.1-5% of the total mass, and the reaction is continued for 1-5 hours. The WHBPU solution was obtained, the solvent was removed by distillation under reduced pressure, and the desired WHBPU was obtained after drying.

The molar ratio of isophorone diisocyanate, dimethylol propionic acid and diethanolamine in step 1) is 1:0.3-0.6:0.35-0.65.

Step 2) Synthesis of AWHBPU

Mix the WHBPU obtained in step 1) with the end-capping agent, the molar ratio of WHBPU and the end-capping agent is 1:0.8-2, then add the catalyst dropwise into the reaction system, the catalyst accounts for 0.5-5% of the total mass after adding, Then add the above mixed solution into pyridine 4-5 times the mass of the mixed solution, and react at 50-120°C for 0.5-5h to obtain the crude AWHBPU, distill under reduced pressure to remove the solvent, and dry to obtain the desired AWHBPU.

Wherein said end-capping agent is a kind of in formic acid, acetic acid, acetic anhydride;

Wherein said catalyst is concentrated sulfuric acid or p-toluenesulfonic acid.

Step 3) Preparation of AWHBPU-PU

The mass percent of each component raw material required for preparing AWHBPU-PU is as follows:

The specific preparation steps of AWHBPU-PU are as follows:

① Weigh the raw materials of each component according to the above ratio, mix ADI with bifunctional polyether or polyester, and heat to 60-120°C for 1-10 hours;

② Add emulsifier dropwise to the above reaction system, and continue to react at 60-120°C for 3-5 hours;

③Reduce the temperature of the above reaction system to 20-70°C, add the AWHBPU obtained in step 2), adjust the viscosity of the system with butanone accounting for 15% of the total mass, add a neutralizer, and react for 1-30 minutes to prepare AWHBPU-PU Prepolymer;

④Use the AWHBPU-PU prepolymer obtained in the previous step to obtain a stable AWHBPU-PU emulsion through high-speed shearing in water;

Wherein the bifunctional polyester or polyether is one or more than two kinds of polyester compounds and polyether compounds containing two hydroxyl groups (-OH) mixed in any proportion;

The ADI is selected from toluene diisocyanate TDI, isophorone diisocyanate IPDI, diphenylmethane diisocyanate MDI, naphthalene-1,5-diisocyanate NDI, hexamethylene diisocyanate HDI, 2,6-diisocyanate Methyl isocyanate hexanoate LDI, 4,4'-methylene-dicyclohexyl diisocyanate H ₁₂ MDI, xylylene diisocyanate XDI or 1,12-dodecyl diisocyanate C ₁₂ DDI a kind of

Described emulsifier is dimethylol propionic acid;

The neutralizing agent is selected from one or more of triethylamine, tri-n-butylamine, sodium hydroxide, potassium hydroxide and calcium hydroxide and mixed in any proportion.

The raw materials required for preparing AWHBPU-PU in step 3) also include a catalyst, and the catalyst is selected from stannous octoate, dibutyltin dilaurate, N-methylmorpholine, and 1,4-dimethylpiperazine One, the amount of catalyst added is 0-0.5% of the total weight of raw materials, and the catalyst is added after mixing ADI with difunctional polyether or polyester in step ① of step 3).

Beneficial effect:

Compared with the traditional hyperbranched waterborne polyurethane fabric coating agent, a kind of hyperbranched waterborne polyurethane blending modified polyurethane fabric coating agent provided by the invention has good emulsion stability, low viscosity and high solid content, After the film is formed, it has good mechanical properties, and the viscosity of the blended emulsion can be reduced by up to 33.8%. At the same time, the coating agent of the present invention also has good mechanical properties after the film is formed, and the tensile strength of the film can be increased by up to 97.9%. The elongation at break increased up to 11.96%.

Detailed ways

Below by embodiment content of the present invention will be further described.

The viscosity of the AWHBPU-PU emulsion obtained in the following examples uses a Brookfield DV II rotary viscometer, selects the LV4 rotor, and rotates at a speed of 100 rpm. At 25 ° C, the water-based polyurethane emulsion with a solid content of 25% is subjected to a shear viscosity test. And the coating samples were prepared into AWHBPU-PU films by the following method; according to the GB/T528-2009 standard, the mechanical properties of the coating agent relative to the film were measured.

Preparation of AWHBPU-PU film samples: cast the AWHBPU-PU emulsion in a mold to form a film with a film thickness of about 1mm, dry it naturally for a week, place it in a vacuum oven at 60°C and vacuum dry it to constant weight, take it out and place it in a desiccator spare.

In order to verify the improvement of the shear viscosity and flexibility of the AWHBPU-PU emulsion, each example prepared a blank sample XA for comparison, and XA is the corresponding linear waterborne polyurethane without adding AWHBPU.

Example 1:

(1) Synthesis of WHBPU

Add 17.8g of IPDI to the reaction flask, heat to 65°C, dissolve 5.4g of DMPA in 27mL of DMF, add it to the reaction flask containing IPDI, keep it at 65°C for 8 hours; then lower the temperature of the reaction system to -10°C, Add 4.2g of DEOA dropwise to the reaction system. After the dropwise addition, keep at -10°C to continue the reaction for 4h; then increase the temperature of the reaction system to 90°C, and add 0.027g of dibutyltin dilaurate as a catalyst, and keep at 90°C The reaction was continued for 3 hours to obtain a colorless transparent liquid, which was distilled under reduced pressure at 70°C for 15 minutes and dried to obtain the desired WHBPU.

(2) Synthesis of AWHBPU

Get the WHBPU10g that step (1) obtains and mix with 10mL acetic anhydride and place it in a reaction flask, and dropwise 0.1g of concentrated sulfuric acid as a catalyst into the mixed solution; then add the above-mentioned mixed solution to 75mL of pyridine, After reacting at ℃ for 2 h, a colorless transparent solution was obtained; the solution was desolvated and dried to obtain the desired AWHBPU.

(3) Preparation of AWHBPU-PU

Mix 70g of polyether N210 (M _n =1000) and 22.5g of toluene diisocyanate TDI in a reaction flask, heat to 85°C and react for 1h; then add 4gDMPA to the reaction system, keep at 85°C for 3h; react After completion, cool the reaction system to 40°C, add 2g of step (2) to obtain AWHBPU, adjust the viscosity of the system with 15g of methyl ethyl ketone, and then add 3.5g of triethylamine (TEA) to neutralize and react for 10min to obtain the prepolymerization of AWHBPU-PU body; the prepolymer was sheared at high speed in water for 5 minutes to obtain a stable AWHBPU-PU emulsion 1.

The corresponding blank sample is 1A

Embodiment 1 emulsion performance:

The comparison results show that compared with traditional hyperbranched waterborne polyurethane, AWHBPU-PU can not only reduce the viscosity of waterborne polyurethane emulsion, but also improve the flexibility of polyurethane film.

Example 2:

(1) Synthesis of WHBPU

Add 8.8g IPDI to the reaction bottle, heat it to 60°C, dissolve 1.61g DMPA in 8mL of DMF, add it to the reaction bottle containing IPDI, keep it at 60°C for 10h; then lower the temperature of the reaction system to -15 ℃, add 1.69g DEOA dropwise to the reaction system, after the dropwise addition, keep at -15℃ to continue the reaction for 4h; then increase the temperature of the reaction system to 80℃, and add 0.605g of stannous octoate as a catalyst, keep at 80℃ The reaction was continued for 5 hours to obtain a colorless transparent liquid, which was distilled under reduced pressure at 70°C for 15 minutes and dried to obtain the desired WHBPU.

(2) Synthesis of AWHBPU

Get the WHBPU 10g that step (1) obtains and mix with 15mL formic acid and place in the reaction flask, and dropwise in the mixed solution as the toluenesulfonic acid 1.25g of catalyzer; Then above-mentioned mixed solution is joined in the 100mL pyridine, in React at 100°C for 4 hours to obtain a colorless transparent solution; desolventize and dry the solution to obtain the desired AWHBPU.

(3) Preparation of AWHBPU-PU

Mix 80g of polyether N220 (M _n =2000) and 34.7g of isophorone diisocyanate IPDI into a reaction flask, add 0.5g of dibutyltin dilaurate as a catalyst, and heat to 120°C for 5h; then Add 7.2g of DMPA to the reaction system, keep at 85°C and continue to react for 5h; after the reaction is completed, cool down to 50°C, add 5.2g of step (2) to obtain AWHBPU, adjust the viscosity of the system with 20g of butanone, then add 5.3gTEA to neutralize the reaction for 20min, That is, the prepolymer of AWHBPU-PU is obtained; the prepolymer is sheared at high speed in water for 5 minutes, and the stable AWHBPU-PU emulsion 2 is obtained.

The corresponding blank sample is 2A

Embodiment 2 emulsion properties:

The comparison results show that compared with traditional hyperbranched waterborne polyurethane, AWHBPU-PU can not only reduce the viscosity of waterborne polyurethane emulsion, but also improve the flexibility of polyurethane film.

Example 3:

(1) Synthesis of WHBPU

Add 70g of IPDI to the reaction bottle, heat it to 75°C, dissolve 16.9g of DMPA in 80mL of DMF, add it to the reaction bottle with IPDI, keep it at 75°C for 5h; then lower the temperature of the reaction system to -5°C, and Add 20g of DEOA dropwise to the reaction system. After the dropwise addition, keep at -5°C and continue the reaction for 3h; then increase the temperature of the reaction system to 100°C, and add 5g of stannous octoate as a catalyst, and keep at 100°C for 2h to obtain It is a colorless transparent liquid, which is distilled under reduced pressure at 70°C for 15 minutes and dried to obtain the desired WHBPU.

(2) Synthesis of AWHBPU

Get the WHBPU 10g that step (1) obtains and mix with 19mL acetic acid and place in the reaction flask, and drop-wise 1.4g of p-toluenesulfonic acid as a catalyst in the mixed solution; then add the above-mentioned mixed solution into 130mL of pyridine, React at 120°C for 5h to obtain a colorless transparent solution; desolventize and dry the solution to obtain the desired AWHBPU.

(3) Preparation of AWHBPU-PU

Mix 36.6g of poly(1,4-butylene adipate) PBA-1000 ( _Mn =1000) and 51.6g of isophorone diisocyanate IPDI into a reaction flask, and add dilauric acid as a catalyst Dibutyltin 0.6g, heated to 100°C to react for 10h; then added 9.6gDMPA to the reaction system, kept at 100°C to continue the reaction for 5h; after the reaction was completed, the temperature was lowered to 70°C, and 12g of step (2) was added to obtain AWHBPU, adjusted with 18g butanone system viscosity, and then add 9.6 tri-n-butylamine for neutralization reaction for 30 minutes to obtain AWHBPU-PU prepolymer; shear the prepolymer in water for 5 minutes to obtain stable AWHBPU-PU emulsion 3.

The corresponding blank sample is 3A

Embodiment 3 emulsion properties:

The comparison results show that compared with traditional hyperbranched waterborne polyurethane, AWHBPU-PU can not only reduce the viscosity of waterborne polyurethane emulsion, but also improve the flexibility of polyurethane film.

Example 4:

(1) Synthesis of WHBPU

Add 35g of IPDI to the reaction flask, heat it to 55°C, dissolve 12.7g of DMPA in 51mL of DMF, add it to the reaction flask containing IPDI, and keep it at 55°C for 12h; then lower the temperature of the reaction system to -25°C, and Add 10g of DEOA dropwise to the reaction system. After the dropwise addition, keep at -5°C and continue the reaction for 6h; then increase the temperature of the reaction system to 110°C, and add 0.0577g of dibutyltin dilaurate as a catalyst, and keep at 110°C for 1h , to obtain a colorless transparent liquid, which was distilled under reduced pressure at 70°C for 15 minutes and dried to obtain the desired WHBPU.

(2) Synthesis of AWHBPU

Get the WHBPU 15g that the 1st step obtains and mix with 18ml acetic anhydride and place in reaction flask, and the concentrated sulfuric acid 0.15g as catalyzer is added dropwise in mixed solution; Above-mentioned mixed solution is joined in 150ml pyridine again, in React at 80°C for 1 h to obtain a colorless transparent solution; desolventize and dry the solution to obtain the desired AWHBPU.

(3) Preparation of AWHBPU-PU

Mix 120g of polyether N220 (M _n =2000) and 24g of isophorone diisocyanate IPDI into a reaction flask, add 0.75g of dibutyltin dilaurate as a catalyst, heat to 90°C for 8h; Add 1.5g DMPA to the system, keep at 90°C and continue to react for 5h; after the reaction is completed, cool down to 50°C, add 2.25g of step (2) to obtain AWHBPU, adjust the viscosity of the system with 22.5 butanone, and then add 1.5g of tri-n-butylamine to neutralize After reacting for 10 minutes, the AWHBPU-PU prepolymer was obtained; the prepolymer was sheared at high speed in water for 5 minutes, and the stable AWHBPU-PU emulsion 4 was obtained.

The corresponding blank sample is 4A

Embodiment 4 emulsion properties:

The comparison results show that compared with traditional hyperbranched waterborne polyurethane, AWHBPU-PU can not only reduce the viscosity of waterborne polyurethane emulsion, but also improve the flexibility of polyurethane film.

Example 5:

(1) Synthesis of WHBPU

Add 50g of IPDI to the reaction flask, heat it to 50°C, and dissolve 15.1g of DMPA in DMF, then add it to the reaction flask containing IPDI, and keep it at 50°C for 15h; Add gDEOA dropwise to the reaction system. After the dropwise addition, keep at 0°C and continue the reaction for 2 hours; then increase the temperature of the reaction system to 85°C, and add 0.09 g of dibutyltin dilaurate as a catalyst, and keep at 85°C to continue the reaction for 4 hours. A colorless transparent liquid was obtained, which was distilled under reduced pressure at 70°C for 15 minutes and dried to obtain the desired WHBPU.

(2) Synthesis of AWHBPU

Get the WHBPU 20g that the 1st step obtains and mix with 25ml acetic anhydride and place in reaction flask, and the concentrated sulfuric acid 0.23g as catalyzer is added dropwise in mixed solution; Above-mentioned mixed solution is joined in 200ml pyridine again, in React at 90°C for 0.5h to obtain a colorless transparent solution; desolventize and dry the solution to obtain the desired AWHBPU.

(3) Preparation of AWHBPU-PU

Mix 93g of polyether N220 (M _n =2000) and 30g of toluene diisocyanate TDI in a reaction flask, heat to 60°C for 5 hours; then add 9g of DMPA to the reaction system and keep it at 60°C for 5 hours; Cool down to 30°C, add 9g of step (2) to obtain AWHBPU, adjust the viscosity of the system with 22.5 butanone, and then add 9g of TEA to neutralize the reaction for 10min to obtain the prepolymer of AWHBPU-PU; After shearing for 5 minutes, stable AWHBPU-PU emulsion 5 was obtained.

The corresponding blank sample is 5A.

Embodiment 5 emulsion properties:

The comparison results show that compared with traditional hyperbranched waterborne polyurethane, AWHBPU-PU can not only reduce the viscosity of waterborne polyurethane emulsion, but also improve the flexibility of polyurethane film.

Embodiment 6:

(1) Synthesis of WHBPU

Add 45g of IPDI to the reaction flask, heat to 80°C, and dissolve 13.6g of DMPA in DMF, then add it to the reaction flask containing IPDI, and keep it at 50°C for 5h; g DEOA is added dropwise to the reaction system. After the dropwise addition, keep at -20°C to continue the reaction for 5 hours; then raise the temperature of the reaction system to 90°C, and add 0.07g of dibutyltin dilaurate as a catalyst, and keep at 90°C to continue the reaction After 3 hours, a colorless transparent liquid was obtained, which was distilled under reduced pressure at 70°C for 15 minutes and dried to obtain the desired WHBPU.

(2) Synthesis of AWHBPU

Get the WHBPU 15g that the 1st step obtains and mix with 18ml acetic anhydride and place in reaction flask, and the concentrated sulfuric acid 0.15g as catalyzer is added dropwise in mixed solution; Above-mentioned mixed solution is joined in 70ml pyridine again, in React at 85°C for 2 hours to obtain a colorless and transparent solution; desolventize and dry the solution to obtain the desired AWHBPU.

(3) Preparation of AWHBPU-PU

Mix 55g of poly-1,4-butylene adipate PBA-2000 (M _n =2000) and 30g of toluene diisocyanate TDI, put it in a reaction bottle, heat it to 70°C for 3 hours, and then add 4g of DMPA, kept at 70°C and continued to react for 5h; after the reaction was completed, cool down to 20°C, add 6g of step (2) to obtain AWHBPU, adjust the viscosity of the system with 15g of methyl ethyl ketone, then add 5g of TEA to neutralize the reaction for 10min, that is, the preform of AWHBPU-PU polymer; the prepolymer was sheared at high speed in water for 30 minutes to obtain stable AWHBPU-PU emulsion 6.

The corresponding blank sample is 6A

Embodiment 6 emulsion properties:

The comparison results show that compared with traditional hyperbranched waterborne polyurethane, AWHBPU-PU can not only reduce the viscosity of waterborne polyurethane emulsion, but also improve the flexibility of polyurethane film.

Claims (4)

1. a hyperbranched water-based polyurethane coating agent is characterized in that the concrete operation steps are as follows: step 1) the synthesis of WHBPU ①Dissolve dimethylolpropionic acid in N,N-dimethylformamide (DMF) at a mass ratio of 1:4~5, and then add the mixture dropwise to isophorone distillate at 50~80°C In isocyanate, react for 5-15 hours; ②Reduce the temperature of the above reaction solution to -25～0℃, add diethanolamine (DEOA), and react for 2～6h; ③The temperature of the above reaction solution is raised to 80-110°C, and dibutyltin dilaurate or stannous octoate is added dropwise to the reaction system according to the ratio of 0.1-5% of the total mass, and the reaction is continued for 1-5 hours. The WHBPU solution was obtained, the solvent was removed by distillation under reduced pressure, and the desired WHBPU was obtained after drying. Step 2) Synthesis of AWHBPU Mix the WHBPU obtained in step 1) with the end-capping agent, the molar ratio of WHBPU and the end-capping agent is 1:0.8-2, then add the catalyst dropwise into the reaction system, the catalyst accounts for 0.5-5% of the total mass after adding, Then add the above mixed solution into pyridine 4-5 times the mass of the mixed solution, and react at 50-120°C for 0.5-5h to obtain the crude AWHBPU, distill under reduced pressure to remove the solvent, and dry to obtain the desired AWHBPU. Wherein said end-capping agent is a kind of in formic acid, acetic acid, acetic anhydride; Wherein said catalyst is concentrated sulfuric acid or p-toluenesulfonic acid. Step 3) Preparation of AWHBPU-PU The mass percent of each component raw material required for preparing AWHBPU-PU is as follows: The specific preparation steps of AWHBPU-PU are as follows: ① Weigh the raw materials of each component according to the above ratio, mix ADI with bifunctional polyether or polyester, add the catalyst dropwise and heat to 60-120°C for 1-10 hours; ② Add emulsifier dropwise to the above reaction system, and continue to react at 60-120°C for 3-5 hours; ③Reduce the temperature of the above reaction system to 20-70°C, add the AWHBPU obtained in step 2), adjust the viscosity of the system with butanone accounting for 15% of the total mass, add a neutralizer, and react for 1-30 minutes to prepare AWHBPU-PU Prepolymer; ④Use the AWHBPU-PU prepolymer obtained in the previous step to obtain a stable AWHBPU-PU emulsion through high-speed shearing in water; Wherein the bifunctional polyester or polyether is one or more than two kinds of polyester compounds and polyether compounds containing two hydroxyl groups (-OH) mixed in any proportion; The ADI is selected from toluene diisocyanate TDI, isophorone diisocyanate IPDI, diphenylmethane diisocyanate MDI, naphthalene-1,5-diisocyanate NDI, hexamethylene diisocyanate HDI, 2,6-diisocyanate Methyl isocyanate hexanoate LDI, 4,4'-methylene-dicyclohexyl diisocyanate H ₁₂ MDI, xylylene diisocyanate XDI or 1,12-dodecyl diisocyanate C ₁₂ DDI a kind of The neutralizing agent is selected from one or more of triethylamine, tri-n-butylamine, sodium hydroxide, potassium hydroxide and calcium hydroxide and mixed in any proportion. 2. hyperbranched water-based polyurethane coating agent as claimed in claim 1, is characterized in that: the mol ratio of isophorone diisocyanate, dimethylol propionic acid and diethanolamine described in its step 1) is 1: 0.3～0.6: 0.35～0.65. 3. The hyperbranched waterborne polyurethane coating agent as claimed in claim 1, characterized in that: the mol ratio of WHBPU and end-capping agent described in its step 2) is 1: 0.8～2. 4. hyperbranched water-based polyurethane coating agent as claimed in claim 1, is characterized in that: in its step 3) in the raw material that AWHBPU-PU needs also comprises catalyzer, described catalyzer is selected from stannous octoate, di One of dibutyltin laurate, N-methylmorpholine, 1,4-dimethylpiperazine, the addition of catalyzer is 0～0.5% of raw material gross weight, and this catalyzer is in step 3) the first step Add after mixing ADI with difunctional polyether or polyester.