High molecular weight waterborne polyurethane resin and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane resin, and discloses high-molecular-weight waterborne polyurethane resin and a preparation method thereof.The waterborne polyurethane resin is synthesized through a prepolymer dispersion method, polyester polyol and isocyanate are pre-polymerized at normal pressure, after a prepolymer is neutralized through a neutralizer, deionized water dissolved with a chain extender is added into the prepolymer, and the high-molecular-weight waterborne polyurethane resin is obtained. Chain extension and dispersion are carried out at the same time; according to the preparation method, a prepolymer dispersion method is adopted, polyester polyol and isocyanate are pre-polymerized under normal pressure, a prepolymer is neutralized by a neutralizer, deionized water dissolved with a chain extender is added into the prepolymer, chain extension and dispersion are carried out at the same time, and the prepared waterborne polyurethane resin has high bonding strength and solvent resistance; water-based polyurethane resin is heated in the film forming process or after film forming to generate a chemical reaction, a stable cross-linked film layer is formed, and the wear resistance and the mechanical property of the water-based polyurethane resin are obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane resins, in particular to a high molecular weight waterborne polyurethane resin and a preparation method thereof. Background Art

[0002] Polyurethane resin is a special polymer. Due to its good wear resistance, corrosion resistance, high strength and low weight, it is widely used in new energy, lithium batteries, photovoltaics, food packaging, automobiles, aerospace, construction, machinery manufacturing, petrochemicals, light industry, metallurgy, electronics, ships and other fields. In recent years, the development of fine chemicals such as polyurethane products has become one of the key directions for various countries to adjust their industrial structure and upgrade. According to the market research report of Beijing Yanjing Bizhi, excluding the impact of 2020, the global polyurethane industry market size is on an upward trend. In 2019, the global polyurethane market size exceeded US$60 billion for the first time, and fell below US$60 billion in 2020. In 2021, the market size increased by more than 5% year-on-year, reaching US$63 billion. Analysts at Beijing Yanjing Bizhi predict that the global polyurethane market size will reach about US$85 billion in 2027.

[0003] Therefore, the market prospects of polyurethane resin are very broad. At present, the global polyurethane market has exceeded 50 billion US dollars and is growing at an annual rate of 5%. In China, the polyurethane resin market is also showing a rapid growth trend. Due to the rapid development of China's automobile, construction and home appliance industries, the demand for polyurethane resin is increasing. At the same time, with the improvement of environmental awareness, the environmental performance of polyurethane resin has also been widely recognized, further expanding its application areas.

[0004] In the future, with the continuous advancement of technology and the continuous expansion of applications, the prospects of the polyurethane resin market will be broader. Especially in the fields of new energy vehicles, intelligent manufacturing, environmentally friendly building materials, etc., the application prospects of polyurethane resin are very broad. At the same time, with the continuous development of the global economy and the improvement of people's living standards, the demand for high-quality and high-performance polyurethane resins will continue to grow.

[0005] Water-based resin is a new type of resin system that uses water instead of organic solvents as a dispersion medium. Water-based resin has excellent properties such as environmental protection, non-flammability, corrosion resistance, wear resistance, and electrical insulation. It is widely used in coatings, adhesives, sealants, fabric and leather coatings and finishing agents, paper and fiber surface treatment agents, etc. The water-based resin industry is a new field of polymer science, with relatively high product added value. Under environmental pressure and consumption upgrading trends, its market size continues to expand.

[0006] However, the polyurethane resins prepared by the prior art are gradually unable to keep up with the increasing performance requirements.

[0007] Based on this, we proposed a high molecular weight waterborne polyurethane resin. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a high molecular weight waterborne polyurethane resin and a preparation method thereof.

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: A high molecular weight waterborne polyurethane resin, the waterborne polyurethane resin is synthesized by a prepolymer dispersion method, polyester polyol and isocyanate are prepolymerized under normal pressure, the prepolymer is neutralized by a neutralizer, deionized water containing a chain extender is added to the prepolymer, and the prepolymer is dispersed while chain extending, and the specific steps include: (1) Prepolymerization: At room temperature and pressure, polyester polyol and isocyanate are pumped into the polyurethane resin reaction kettle, and the stirring device is turned on to stir the materials; (2) Reflux: Add additives and catalysts to the prepolymer and reflux for 3-5 hours at 60°C; (3) Neutralization reaction: When the isocyanate index reaches 1, cool down to below 50°C, transfer to a high-speed disperser, and add hydrazine hydrate for neutralization; (4) Dispersion emulsification and chain extension reaction: Deionized water containing a chain extender is added to disperse the prepolymer in the deionized water under the action of shear force to carry out a chain extension reaction to generate a high molecular weight waterborne polyurethane resin; Deionized water is added for emulsification, so that the prepolymer is dispersed in water under the action of shear force. The dispersion process is carried out at a low temperature of 35°C to reduce the reaction activity of -NCO and water. The water participating in the reaction is equivalent to a chain extender. Then, ethylenediamine and dimethylolbutyric acid with high reaction activity are used to extend the chain in water to quickly promote the chain growth reaction and generate a high molecular weight waterborne polyurethane. (5) Finished product packaging: When the polymer viscosity reaches 1000 mPa·s, cool the material to 40°C, open the nitrogen control valve to introduce nitrogen into the flask, open the flask bottom valve, and press the material into a 200 kg packaging barrel to package the finished polyurethane resin. During packaging, filter out impurities through a stainless steel filter, and transport the finished product to the finished product warehouse by forklift.

[0010] As a further technical solution, the diisocyanate in step (1) is an aliphatic diisocyanate.

[0011] As a further technical solution, the polyester polyol in step (1) is a polyadipic acid-based polyester polyol having a molecular weight of 2500 and a hydroxyl value of 55 KOHmg / g.

[0012] As a further technical solution: in step (1), the molar ratio of polyester polyol to isocyanate is 1-2:1.

[0013] As a further technical solution: in step (2), the amount of catalyst added is 0.1-0.12% of the mass of the prepolymer; The catalyst is stannous octoate.

[0014] As a further technical solution: the auxiliary agent in step (2) is a defoaming agent, an antioxidant, or a modifier; The mass ratio of defoamer to antioxidant and modifier is 2:1:5-8; The amount of additive added is 1-1.5% of the prepolymer mass; The defoamer is an organosilicon defoamer; The antioxidant is 2,6-di-tert-butyl-4-methylphenol; As a further technical solution, the preparation method of the modifier is: First, weigh rosin, then add the rosin to fumaric acid, heat to 200° C. under inert atmosphere protection, and stir and react for 1.5 hours to obtain pre-modified rosin; The pre-modified rosin and modified soybean oil obtained above are added to the reactor in sequence, and then pentaerythritol is added. Under the protection of an inert atmosphere, the temperature is adjusted to 80° C., and the mixture is stirred and reacted for 1 hour. Then, the ethylenediamine solution is added, the temperature is adjusted to 120° C., and the mixture is stirred and reacted for 4 hours. Then, the mixture is discharged, cooled, washed with water until neutral, and dried to obtain a modifier. The mixing mass ratio of the rosin to the fumaric acid is 10:1-1.5; The inert atmosphere is nitrogen; The mixing mass ratio of the pre-modified rosin and modified soybean oil is 5:2; The mixing mass ratio of pre-modified rosin and pentaerythritol is 15:2-3; The volume ratio of the ethylenediamine solution to pentaerythritol is 2:1; The mass fraction of ethylenediamine solution is 12%; As a further technical solution: the preparation method of the modified soybean oil is: The soybean oil is dried to a moisture content of less than 5%; The dried soybean oil was added into the reactor, and then vacuumed for 20 minutes and condensed and refluxed for 40 minutes; After heating to 85°C, benzoyl peroxide was added, stirred and reacted for 40 minutes, acrylic acid was added, the temperature was adjusted to 120°C, kept warm, stirred and reacted for 4 hours, cooled to 80°C, a neutralizer was added for neutralization reaction, the pH was adjusted to 7.8, and then dried to a moisture content of 5% to obtain modified soybean oil; The vacuuming is to vacuumize to 0.1 Pa; The amount of benzoyl peroxide added was 0.5% of the mass of soybean oil; The amount of acrylic acid added is 10% of the mass of soybean oil; The neutralizing agent is an aqueous ammonia solution; The mass fraction of the ammonia solution is 12.5%.

[0015] As a further technical solution: in step (4), the mass ratio of the chain extender to the prepolymer in the deionized water containing the chain extender is 1:20-25; The molar ratio of deionized water to polyester polyol is 1:1; The chain extender is ethylenediamine and dimethylolbutyric acid; Among them, the mixing mass ratio of ethylenediamine and dihydroxymethylbutyric acid is 3:1.

[0016] As a further technical solution, in step (5), nitrogen is introduced until the pressure in the reactor reaches 0.3 MPa.

[0017] The molecular weight of high molecular weight waterborne polyurethane resin is between 15,000 and 25,000.

[0018] Compared with the prior art, the present invention provides a high molecular weight waterborne polyurethane resin, which has the following beneficial effects: The present invention adopts a prepolymer dispersion method to prepolymerize polyester polyol and isocyanate under normal pressure, and after the prepolymer is neutralized by a neutralizer, deionized water containing a chain extender is added to the prepolymer to prepare an aqueous polyurethane resin while extending the chain and dispersing the prepolymer. The aqueous polyurethane resin has high bonding strength and solvent resistance. The aqueous polyurethane resin is heated during or after film formation to generate a chemical reaction to form a stable cross-linked film layer, and the wear resistance and mechanical properties of the aqueous polyurethane resin are significantly improved.

[0019] By introducing a modifier prepared by a specific method in the preparation process of the waterborne polyurethane resin, the comprehensive performance of the waterborne polyurethane resin can be further improved, especially the wear resistance is significantly improved. The modifier introduced in the present invention can effectively improve the wear resistance of the waterborne polyurethane coating without changing the hardness of the waterborne polyurethane coating, thereby effectively avoiding the brittleness caused by excessive hardness. In order to further improve the performance of the waterborne polyurethane resin, the present invention introduces modified soybean oil in the preparation process of the modifier. The modifier prepared after the introduction of the modified soybean oil can further introduce branch points into the main chain of the waterborne polyurethane resin due to the introduction of multiple active groups, thereby obtaining a more stable network structure, and increasing the number of cross-linking points, obtaining a more compact cross-linking structure, so that the mechanical properties, hydrophobicity and stain resistance of the waterborne polyurethane can be further enhanced, which is manifested in significantly improving the water contact angle of the coating surface after the waterborne polyurethane resin is cured, and the unsaturated double bonds contained in the modifier can be further oxidatively cross-linked during curing, thereby optimizing the performance of the polyurethane coating, including improving its water resistance and mechanical properties.

[0020] The waterborne polyurethane resin prepared by the invention not only enhances its performance, but also can broaden the application field of the waterborne polyurethane. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the synthesis reaction of waterborne polyurethane resin; Figure 2 This is a flow chart of the synthesis steps of waterborne polyurethane resin. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Example 1

[0023] A high molecular weight waterborne polyurethane resin, the waterborne polyurethane resin is synthesized by a prepolymer dispersion method, polyester polyol and isocyanate are prepolymerized under normal pressure, the prepolymer is neutralized by a neutralizer, deionized water containing a chain extender is added to the prepolymer, and the prepolymer is dispersed while chain extending, and the specific steps include: (1) Prepolymerization: The polyester polyol and isocyanate are pumped into the polyurethane resin reaction tank at room temperature and pressure, and the stirring device is turned on to stir the materials; the diisocyanate is an aliphatic diisocyanate.

[0024] The polyester polyol is a polyadipic acid-based polyester polyol having a molecular weight of 2500 and a hydroxyl value of 55 KOHmg / g.

[0025] The molar ratio of polyester polyol to isocyanate is 1:1.

[0026] (2) Reflux: Add additives and catalysts to the prepolymer and reflux for 3 hours at 60°C. The amount of catalyst added is 0.1% of the prepolymer mass. The catalyst is stannous octoate.

[0027] The additives are defoamers, antioxidants, and modifiers; The mass ratio of defoamer to antioxidant and modifier is 2:1:5; The amount of additive added is 1% of the prepolymer mass; The defoamer is an organosilicon defoamer; The antioxidant is 2,6-di-tert-butyl-4-methylphenol; The preparation method of the modifier is: First, weigh rosin, then add the rosin to fumaric acid, heat to 200° C. under inert atmosphere protection, and stir and react for 1.5 hours to obtain pre-modified rosin; The pre-modified rosin and modified soybean oil obtained above are added to the reactor in sequence, and then pentaerythritol is added. Under the protection of an inert atmosphere, the temperature is adjusted to 80° C., and the mixture is stirred and reacted for 1 hour. Then, the ethylenediamine solution is added, the temperature is adjusted to 120° C., and the mixture is stirred and reacted for 4 hours. Then, the mixture is discharged, cooled, washed with water until neutral, and dried to obtain a modifier. The mixing mass ratio of the rosin to the fumaric acid is 10:1; The inert atmosphere is nitrogen; The mixing mass ratio of the pre-modified rosin and modified soybean oil is 5:2; The mixing mass ratio of pre-modified rosin and pentaerythritol is 15:2; The volume ratio of the ethylenediamine solution to pentaerythritol is 2:1; The mass fraction of ethylenediamine solution is 12%; The preparation method of modified soybean oil is as follows: The soybean oil is dried to a moisture content of less than 5%; The dried soybean oil was added into the reactor, and then vacuumed for 20 minutes and condensed and refluxed for 40 minutes; After heating to 85°C, benzoyl peroxide was added, stirred and reacted for 40 minutes, acrylic acid was added, the temperature was adjusted to 120°C, kept warm, stirred and reacted for 4 hours, cooled to 80°C, a neutralizer was added for neutralization reaction, the pH was adjusted to 7.8, and then dried to a moisture content of 5% to obtain modified soybean oil; The vacuuming is to vacuumize to 0.1 Pa; The amount of benzoyl peroxide added was 0.5% of the mass of soybean oil; The amount of acrylic acid added is 10% of the mass of soybean oil; The neutralizing agent is an aqueous ammonia solution; The mass fraction of the ammonia solution is 12.5%.

[0028] (3) Neutralization reaction: When the isocyanate index reaches 1, cool down to below 50°C, transfer to a high-speed disperser, and add hydrazine hydrate for neutralization; (4) Dispersion emulsification and chain extension reaction: Deionized water containing a chain extender is added to disperse the prepolymer in the deionized water under the action of shear force to carry out a chain extension reaction to generate a high molecular weight waterborne polyurethane resin; Deionized water is added for emulsification, so that the prepolymer is dispersed in water under the action of shear force. The dispersion process is carried out at a low temperature of 35°C to reduce the reaction activity of -NCO and water. The water participating in the reaction is equivalent to a chain extender. Then, ethylenediamine and dihydroxymethylbutyric acid with high reaction activity are used to extend the chain in water to quickly promote the chain growth reaction and generate a high molecular weight water-based polyurethane. The mass ratio of the chain extender to the prepolymer in the deionized water containing the chain extender is 1:20. The molar ratio of deionized water to polyester polyol is 1:1; The chain extender is ethylenediamine and dimethylolbutyric acid; Among them, the mixing mass ratio of ethylenediamine and dihydroxymethylbutyric acid is 3:1.

[0029] (5) Finished product packaging: When the polymer viscosity reaches 1000 mPa·s, cool the material to 40°C, open the nitrogen control valve to introduce nitrogen into the kettle, open the bottom valve of the kettle, and press the material into a 200 kg packaging barrel to package the finished polyurethane resin. During packaging, filter out impurities through a stainless steel filter. The finished product is transported to the finished product warehouse by a forklift; introduce nitrogen until the pressure in the reactor reaches 0.3 Mpa. Example 2

[0030] A high molecular weight waterborne polyurethane resin, the waterborne polyurethane resin is synthesized by a prepolymer dispersion method, polyester polyol and isocyanate are prepolymerized under normal pressure, the prepolymer is neutralized by a neutralizer, deionized water containing a chain extender is added to the prepolymer, and the prepolymer is dispersed while chain extending, and the specific steps include: (1) Prepolymerization: The polyester polyol and isocyanate are pumped into the polyurethane resin reaction tank at room temperature and pressure, and the stirring device is turned on to stir the materials; the diisocyanate is an aliphatic diisocyanate.

[0031] The polyester polyol is a polyadipic acid-based polyester polyol having a molecular weight of 2500 and a hydroxyl value of 55 KOHmg / g.

[0032] The molar ratio of polyester polyol to isocyanate is 1.2:1.

[0033] (2) Reflux: Add additives and catalysts to the prepolymer and reflux for 3.5 hours at 60°C. The amount of catalyst added is 0.11% of the prepolymer mass. The catalyst is stannous octoate.

[0034] The additives are defoamers, antioxidants, and modifiers; The mass ratio of defoamer to antioxidant and modifier is 2:1:6; The amount of additive added is 1.2% of the prepolymer mass; The defoamer is an organosilicon defoamer; The antioxidant is 2,6-di-tert-butyl-4-methylphenol; The preparation method of the modifier is: First, weigh rosin, then add the rosin to fumaric acid, heat to 200° C. under inert atmosphere protection, and stir and react for 1.5 hours to obtain pre-modified rosin; The pre-modified rosin and modified soybean oil obtained above are added to the reactor in sequence, and then pentaerythritol is added. Under the protection of an inert atmosphere, the temperature is adjusted to 80° C., and the mixture is stirred and reacted for 1 hour. Then, the ethylenediamine solution is added, the temperature is adjusted to 120° C., and the mixture is stirred and reacted for 4 hours. Then, the mixture is discharged, cooled, washed with water until neutral, and dried to obtain a modifier. The mixing mass ratio of the rosin to the fumaric acid is 10:1.2; The inert atmosphere is nitrogen; The mixing mass ratio of the pre-modified rosin and modified soybean oil is 5:2; The mixing mass ratio of pre-modified rosin and pentaerythritol is 15:2.5; The volume ratio of the ethylenediamine solution to pentaerythritol is 2:1; The mass fraction of ethylenediamine solution is 12%; The preparation method of modified soybean oil is as follows: The soybean oil is dried to a moisture content of less than 5%; The dried soybean oil was added into the reactor, and then vacuumed for 20 minutes and condensed and refluxed for 40 minutes; After heating to 85°C, benzoyl peroxide was added, stirred and reacted for 40 minutes, acrylic acid was added, the temperature was adjusted to 120°C, kept warm, stirred and reacted for 4 hours, cooled to 80°C, a neutralizer was added for neutralization reaction, the pH was adjusted to 7.8, and then dried to a moisture content of 5% to obtain modified soybean oil; The vacuuming is to vacuumize to 0.1 Pa; The amount of benzoyl peroxide added was 0.5% of the mass of soybean oil; The amount of acrylic acid added is 10% of the mass of soybean oil; The neutralizing agent is an aqueous ammonia solution; The mass fraction of the ammonia solution is 12.5%.

[0035] (3) Neutralization reaction: When the isocyanate index reaches 1, cool down to below 50°C, transfer to a high-speed disperser, and add hydrazine hydrate for neutralization; (4) Dispersion emulsification and chain extension reaction: Deionized water containing a chain extender is added to disperse the prepolymer in the deionized water under the action of shear force to carry out a chain extension reaction to generate a high molecular weight waterborne polyurethane resin; Deionized water is added for emulsification, so that the prepolymer is dispersed in water under the action of shear force. The dispersion process is carried out at a low temperature of 35°C to reduce the reaction activity of -NCO and water. The water participating in the reaction is equivalent to a chain extender. Then, ethylenediamine and dihydroxymethylbutyric acid with high reaction activity are used to extend the chain in water to quickly promote the chain growth reaction and generate a high molecular weight water-based polyurethane. The mass ratio of the chain extender to the prepolymer in the deionized water containing the chain extender is 1:22. The molar ratio of deionized water to polyester polyol is 1:1; The chain extender is ethylenediamine and dimethylolbutyric acid; Among them, the mixing mass ratio of ethylenediamine and dihydroxymethylbutyric acid is 3:1.

[0036] (5) Finished product packaging: When the polymer viscosity reaches 1000 mPa·s, cool the material to 40°C, open the nitrogen control valve to introduce nitrogen into the kettle, open the bottom valve of the kettle, and press the material into a 200 kg packaging barrel to package the finished polyurethane resin. During packaging, filter out impurities through a stainless steel filter. The finished product is transported to the finished product warehouse by a forklift; introduce nitrogen until the pressure in the reactor reaches 0.3 Mpa. Example 3

[0037] A high molecular weight waterborne polyurethane resin, the waterborne polyurethane resin is synthesized by a prepolymer dispersion method, polyester polyol and isocyanate are prepolymerized under normal pressure, the prepolymer is neutralized by a neutralizer, deionized water containing a chain extender is added to the prepolymer, and the prepolymer is dispersed while chain extending, and the specific steps include: (1) Prepolymerization: The polyester polyol and isocyanate are pumped into the polyurethane resin reaction tank at room temperature and pressure, and the stirring device is turned on to stir the materials; the diisocyanate is an aliphatic diisocyanate.

[0038] The polyester polyol is a polyadipic acid-based polyester polyol having a molecular weight of 2500 and a hydroxyl value of 55 KOHmg / g.

[0039] The molar ratio of polyester polyol to isocyanate is 1.8:1.

[0040] (2) Reflux: Add additives and catalysts to the prepolymer and reflux for 4 hours at 60°C. The amount of catalyst added is 0.1% of the prepolymer mass. The catalyst is stannous octoate.

[0041] The additives are defoamers, antioxidants, and modifiers; The mass ratio of defoamer to antioxidant and modifier is 2:1:7; The amount of additive added is 1.3% of the prepolymer mass; The defoamer is an organosilicon defoamer; The antioxidant is 2,6-di-tert-butyl-4-methylphenol; The preparation method of the modifier is: First, weigh rosin, then add the rosin to fumaric acid, heat to 200° C. under inert atmosphere protection, and stir and react for 1.5 hours to obtain pre-modified rosin; The pre-modified rosin and modified soybean oil obtained above are added to the reactor in sequence, and then pentaerythritol is added. Under the protection of an inert atmosphere, the temperature is adjusted to 80° C., and the mixture is stirred and reacted for 1 hour. Then, the ethylenediamine solution is added, the temperature is adjusted to 120° C., and the mixture is stirred and reacted for 4 hours. Then, the mixture is discharged, cooled, washed with water until neutral, and dried to obtain a modifier. The mixing mass ratio of the rosin to the fumaric acid is 10:1.4; The inert atmosphere is nitrogen; The mixing mass ratio of the pre-modified rosin and modified soybean oil is 5:2; The mixing mass ratio of pre-modified rosin and pentaerythritol is 15:2.8; The volume ratio of the ethylenediamine solution to pentaerythritol is 2:1; The mass fraction of ethylenediamine solution is 12%; The preparation method of modified soybean oil is as follows: The soybean oil is dried to a moisture content of less than 5%; The dried soybean oil was added into the reactor, and then vacuumed for 20 minutes and condensed and refluxed for 40 minutes; After heating to 85°C, benzoyl peroxide was added, stirred and reacted for 40 minutes, acrylic acid was added, the temperature was adjusted to 120°C, kept warm, stirred and reacted for 4 hours, cooled to 80°C, a neutralizer was added for neutralization reaction, the pH was adjusted to 7.8, and then dried to a moisture content of 5% to obtain modified soybean oil; The vacuuming is to vacuumize to 0.1 Pa; The amount of benzoyl peroxide added was 0.5% of the mass of soybean oil; The amount of acrylic acid added is 10% of the mass of soybean oil; The neutralizing agent is an aqueous ammonia solution; The mass fraction of the ammonia solution is 12.5%.

[0042] (3) Neutralization reaction: When the isocyanate index reaches 1, cool down to below 50°C, transfer to a high-speed disperser, and add hydrazine hydrate for neutralization; (4) Dispersion emulsification and chain extension reaction: Deionized water containing a chain extender is added to disperse the prepolymer in the deionized water under the action of shear force to carry out a chain extension reaction to generate a high molecular weight waterborne polyurethane resin; Deionized water is added for emulsification, so that the prepolymer is dispersed in water under the action of shear force. The dispersion process is carried out at a low temperature of 35°C to reduce the reaction activity of -NCO and water. The water participating in the reaction is equivalent to a chain extender. Then, ethylenediamine and dihydroxymethylbutyric acid with high reaction activity are used to extend the chain in water to quickly promote the chain growth reaction and generate a high molecular weight water-based polyurethane. The mass ratio of the chain extender to the prepolymer in the deionized water containing the chain extender is 1:24. The molar ratio of deionized water to polyester polyol is 1:1; The chain extender is ethylenediamine and dimethylolbutyric acid; Among them, the mixing mass ratio of ethylenediamine and dihydroxymethylbutyric acid is 3:1.

[0043] (5) Finished product packaging: When the polymer viscosity reaches 1000 mPa·s, cool the material to 40°C, open the nitrogen control valve to introduce nitrogen into the kettle, open the bottom valve of the kettle, and press the material into a 200 kg packaging barrel to package the finished polyurethane resin. During packaging, filter out impurities through a stainless steel filter. The finished product is transported to the finished product warehouse by a forklift; introduce nitrogen until the pressure in the reactor reaches 0.3 Mpa. Example 4

[0044] A high molecular weight waterborne polyurethane resin, the waterborne polyurethane resin is synthesized by a prepolymer dispersion method, polyester polyol and isocyanate are prepolymerized under normal pressure, the prepolymer is neutralized by a neutralizer, deionized water containing a chain extender is added to the prepolymer, and the prepolymer is dispersed while chain extending, and the specific steps include: (1) Prepolymerization: The polyester polyol and isocyanate are pumped into the polyurethane resin reaction tank at room temperature and pressure, and the stirring device is turned on to stir the materials; the diisocyanate is an aliphatic diisocyanate.

[0045] The polyester polyol is a polyadipic acid-based polyester polyol having a molecular weight of 2500 and a hydroxyl value of 55 KOHmg / g.

[0046] The molar ratio of polyester polyol to isocyanate is 2:1.

[0047] (2) Reflux: Add additives and catalysts to the prepolymer and reflux for 5 hours at 60°C. The amount of catalyst added is 0.12% of the prepolymer mass. The catalyst is stannous octoate.

[0048] The additives are defoamers, antioxidants, and modifiers; The mass ratio of defoamer to antioxidant and modifier is 2:1:8; The amount of additive added is 1.5% of the prepolymer mass; The defoamer is an organosilicon defoamer; The antioxidant is 2,6-di-tert-butyl-4-methylphenol; The preparation method of the modifier is: First, weigh rosin, then add the rosin to fumaric acid, heat to 200° C. under inert atmosphere protection, and stir and react for 1.5 hours to obtain pre-modified rosin; The pre-modified rosin and modified soybean oil obtained above are added to the reactor in sequence, and then pentaerythritol is added. Under the protection of an inert atmosphere, the temperature is adjusted to 80° C., and the mixture is stirred and reacted for 1 hour. Then, the ethylenediamine solution is added, the temperature is adjusted to 120° C., and the mixture is stirred and reacted for 4 hours. Then, the mixture is discharged, cooled, washed with water until neutral, and dried to obtain a modifier. The mixing mass ratio of the rosin to the fumaric acid is 10:1.5; The inert atmosphere is nitrogen; The mixing mass ratio of the pre-modified rosin and modified soybean oil is 5:2; The mixing mass ratio of pre-modified rosin and pentaerythritol is 15:3; The volume ratio of the ethylenediamine solution to pentaerythritol is 2:1; The mass fraction of ethylenediamine solution is 12%; The preparation method of modified soybean oil is as follows: The soybean oil is dried to a moisture content of less than 5%; The dried soybean oil was added into the reactor, and then vacuumed for 20 minutes and condensed and refluxed for 40 minutes; After heating to 85°C, benzoyl peroxide was added, stirred and reacted for 40 minutes, acrylic acid was added, the temperature was adjusted to 120°C, kept warm, stirred and reacted for 4 hours, cooled to 80°C, a neutralizer was added for neutralization reaction, the pH was adjusted to 7.8, and then dried to a moisture content of 5% to obtain modified soybean oil; The vacuuming is to vacuumize to 0.1 Pa; The amount of benzoyl peroxide added was 0.5% of the mass of soybean oil; The amount of acrylic acid added is 10% of the mass of soybean oil; The neutralizing agent is an aqueous ammonia solution; The mass fraction of the ammonia solution is 12.5%.

[0049] (3) Neutralization reaction: When the isocyanate index reaches 1, cool down to below 50°C, transfer to a high-speed disperser, and add hydrazine hydrate for neutralization; (4) Dispersion emulsification and chain extension reaction: Deionized water containing a chain extender is added to disperse the prepolymer in the deionized water under the action of shear force to carry out a chain extension reaction to generate a high molecular weight waterborne polyurethane resin; Deionized water is added for emulsification, so that the prepolymer is dispersed in water under the action of shear force. The dispersion process is carried out at a low temperature of 35°C to reduce the reaction activity of -NCO and water. The water participating in the reaction is equivalent to a chain extender. Then, ethylenediamine and dihydroxymethylbutyric acid with high reaction activity are used to extend the chain in water to quickly promote the chain growth reaction and generate a high molecular weight water-based polyurethane. The mass ratio of the chain extender to the prepolymer in the deionized water containing the chain extender is 1:25. The molar ratio of deionized water to polyester polyol is 1:1; The chain extender is ethylenediamine and dimethylolbutyric acid; Among them, the mixing mass ratio of ethylenediamine and dihydroxymethylbutyric acid is 3:1.

[0050] (5) Finished product packaging: When the polymer viscosity reaches 1000 mPa·s, cool the material to 40°C, open the nitrogen control valve to introduce nitrogen into the kettle, open the bottom valve of the kettle, and press the material into a 200 kg packaging barrel to package the finished polyurethane resin. During packaging, filter out impurities through a stainless steel filter. The finished product is transported to the finished product warehouse by a forklift; introduce nitrogen until the pressure in the reactor reaches 0.3 Mpa.

[0051] The following is a comparative example: Comparative Example 1: On the basis of Example 1, no modifier is added, and the rest of the technical scheme is consistent with the technical scheme of Example 1.

[0052] Comparative Example 2: On the basis of Example 1, modified soybean oil is not added in the process of preparing the modifier, and the rest of the technical scheme is consistent with the technical scheme of Example 1.

[0053] Comparative Example 3: On the basis of Example 1, the modified soybean oil in the preparation process of the modifier was replaced with conventional untreated soybean oil, and the rest of the technical scheme was consistent with the technical scheme of Example 1.

[0054] test: Stability testing; Adding filler calcium carbonate to the samples of the embodiment and the comparative example, mixing them evenly, to obtain a waterborne polyurethane coating, wherein the amount of calcium carbonate added accounts for 30% of the total mass of the waterborne polyurethane coating. The mixture is placed in a centrifuge tube, put into a centrifuge, and centrifuged at 3000 r / min for 30 minutes at room temperature, and then observing the morphology of the waterborne polyurethane coating to characterize the centrifugal stability. Table 1 Centrifugal stability Example 1 No stratification or precipitation Example 2 Layering, no precipitation Example 3 Layering, no precipitation Example 4 Layering, no precipitation Comparative Example 1 Micro-stratification, small amount of precipitation Comparative Example 2 Micro-stratification, no precipitation Comparative Example 3 Micro-stratification, no precipitation It can be seen from Table 1 that the waterborne polyurethane resin prepared by the present invention has excellent stability. Through the experimental comparison between the embodiment and the comparative example, it can be obviously seen that after the introduction of the modifier, the stability of the prepared waterborne polyurethane resin can be significantly improved. Compared with conventional soybean oil, the modified soybean oil can further improve the modification and enhancement effect of the modifier on the waterborne polyurethane resin.

[0055] The waterborne polyurethane coating prepared above is uniformly coated on the surface of the glass plate, and then dried under the same conditions to form a coating film with a thickness difference of no more than 0.1 mm; A surface contact angle tester (Dataphysics, Germany, OCA40 Micro) was used to perform contact angle test (WCA) to characterize the hydrophobic properties of waterborne polyurethane resin coatings. Table 2 Water contact angle° Example 1 157.6 Example 2 158.1 Example 3 158.5 Example 4 157.3 Comparative Example 1 140.9 Comparative Example 2 149.3 Comparative Example 3 150.2 It can be seen from Table 2 that the prepared waterborne polyurethane resin has a higher water contact angle, indicating that the hydrophobicity of the formed waterborne polyurethane resin is relatively good.

[0056] Wear resistance test: Use 800 mesh sandpaper to move on the coating surface, press a 100g weight on the sandpaper, and move 10cm each time. This is one cycle, and repeat 10 cycles. After each cycle, test the surface contact angle of the coating to characterize the wear resistance. Table 3 Water contact angle° Example 1 154.5 Example 2 155.2 Example 3 155.3 Example 4 153.2 Comparative Example 1 134.7 Comparative Example 2 145.5 Comparative Example 3 146.4 It can be seen from Table 3 that the waterborne polyurethane resin prepared by the present invention has high wear resistance after curing.

[0057] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high molecular weight waterborne polyurethane resin, characterized in that: The waterborne polyurethane resin is synthesized by the prepolymer dispersion method, which is prepared by prepolymerizing polyester polyol and isocyanate under normal pressure. After the prepolymer is neutralized by a neutralizer, deionized water containing a chain extender is added to the prepolymer to extend the chain while dispersing. The specific steps include: (1) Prepolymerization: At room temperature and pressure, polyester polyol and isocyanate are pumped into the polyurethane resin reaction kettle, and the stirring device is turned on to stir the materials; (2) Reflux: Add additives and catalysts to the prepolymer and reflux for 3-5 hours at 60°C; (3) Neutralization reaction: When the isocyanate index reaches 1, cool down to below 50°C, transfer to a high-speed disperser, and add hydrazine hydrate for neutralization; (4) Dispersion emulsification and chain extension reaction: Deionized water containing a chain extender is added to disperse the prepolymer in the deionized water under the action of shear force to carry out a chain extension reaction to generate a high molecular weight waterborne polyurethane resin; (5) Finished product packaging: When the polymer viscosity reaches 1000 mPa·s, cool the material to 40°C, open the nitrogen control valve to introduce nitrogen into the kettle, open the bottom valve of the kettle, and press the material into the packaging barrel to package the finished polyurethane resin.

2. A high molecular weight waterborne polyurethane resin according to claim 1, characterized in that: The diisocyanate in step (1) is an aliphatic diisocyanate.

3. A high molecular weight waterborne polyurethane resin according to claim 1, characterized in that: The polyester polyol in step (1) is a polyadipic acid-based polyester polyol having a molecular weight of 2500 and a hydroxyl value of 55 KOHmg / g.

4. A high molecular weight waterborne polyurethane resin according to claim 1, characterized in that: In step (1), the molar ratio of polyester polyol to isocyanate is 1-2:

1.

5. A high molecular weight waterborne polyurethane resin according to claim 1, characterized in that: In step (2), the amount of catalyst added is 0.1-0.12% of the mass of the prepolymer; The catalyst is stannous octoate.

6. A high molecular weight waterborne polyurethane resin according to claim 1, characterized in that: The auxiliary agent in step (2) is a defoaming agent, an antioxidant, and a modifier; The mass ratio of defoamer to antioxidant and modifier is 2:1:5-8; The amount of additive added is 1-1.5% of the prepolymer mass; The defoamer is an organosilicon defoamer; The antioxidant is 2,6-di-tert-butyl-4-methylphenol.

7. A high molecular weight waterborne polyurethane resin according to claim 6, characterized in that: The preparation method of the modifier is: First, weigh rosin, then add the rosin to fumaric acid, heat to 200° C. under inert atmosphere protection, and stir and react for 1.5 hours to obtain pre-modified rosin; The pre-modified rosin and modified soybean oil obtained above are added to the reactor in sequence, and then pentaerythritol is added. Under the protection of an inert atmosphere, the temperature is adjusted to 80° C., and the mixture is stirred and reacted for 1 hour. Then, the ethylenediamine solution is added, the temperature is adjusted to 120° C., and the mixture is stirred and reacted for 4 hours. Then, the mixture is discharged, cooled, washed with water until neutral, and dried to obtain a modifier. The mixing mass ratio of the rosin to the fumaric acid is 10:1-1.5; The inert atmosphere is nitrogen; The mixing mass ratio of the pre-modified rosin and modified soybean oil is 5:2; The mixing mass ratio of pre-modified rosin and pentaerythritol is 15:2-3; The volume ratio of the ethylenediamine solution to pentaerythritol is 2:1; The mass fraction of ethylenediamine solution is 12%.

8. A high molecular weight waterborne polyurethane resin according to claim 7, characterized in that: The modified soybean oil preparation method is: The soybean oil is dried to a moisture content of less than 5%; The dried soybean oil was added into the reactor, and then vacuumed for 20 minutes and condensed and refluxed for 40 minutes; After heating to 85°C, benzoyl peroxide was added, stirred and reacted for 40 minutes, acrylic acid was added, the temperature was adjusted to 120°C, kept warm, stirred and reacted for 4 hours, cooled to 80°C, a neutralizer was added for neutralization reaction, the pH was adjusted to 7.8, and then dried to a moisture content of 5% to obtain modified soybean oil; The vacuuming is to vacuumize to 0.1 Pa; The amount of benzoyl peroxide added was 0.5% of the mass of soybean oil; The amount of acrylic acid added is 10% of the mass of soybean oil; The neutralizing agent is an aqueous ammonia solution; The mass fraction of the ammonia solution is 12.5%.

9. A high molecular weight waterborne polyurethane resin according to claim 1, characterized in that: In step (4), the mass ratio of the chain extender to the prepolymer in the deionized water containing the chain extender is 1:20-25; The molar ratio of deionized water to polyester polyol is 1:1; The chain extender is ethylenediamine and dimethylolbutyric acid; Among them, the mixing mass ratio of ethylenediamine and dihydroxymethylbutyric acid is 3:

1.

10. A high molecular weight waterborne polyurethane resin according to claim 1, characterized in that: In step (5), nitrogen is introduced until the pressure in the reactor reaches 0.3 MPa.

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